Comparison of physicochemical properties and cooking edibility of waxy and non-waxy proso millet (Panicum miliaceum L.)

Changes in the grain quality of foxtail millet released in China from the 1970s to the 2020s

Foxtail millet (Setaria italica (L.) P. Beauv.) is popular for its medicinal and edible properties and is an important strategic reserve crop for future complex climates. In this study, the genetic diversity of 5 representative foxtail millet genotypes released from the 1970s to the 2020s was examined for their appearance quality, nutritional quality, amino acid contents, culinary quality and aroma profiles. The trend of these indicators over the 60 years of cultivar release was revealed. The results revealed that the genetic gains of b*, yellow pigment content (YPC), breakdown viscosity (BD), setback viscosity (SB), and consistency (CS) were 0.45 %, 0.93 %, 0.34 %, -1.97 %, and - 0.68 %, respectively. The replacement of foxtail millet cultivars improved their appearance quality, culinary quality, and aroma and decreased their nutritional quality. Overall, a compensation effect exists between nutritional quality and organoleptic quality. The transitional foxtail millet variety has advantages over both the old varieties and modern varieties. Therefore, breeders need to focus on improving the nutritional quality of foxtail millet and utilize the quality advantages of the transitional variety in the future.

Effect of sowing date on physicochemical properties of waxy and non-waxy proso millet (Panicum miliaceum L.) starches

In this experiment, waxy (Shuzi, P1) and non-waxy (Ningmei No. 14, P2) proso millet were used as experimental materials to study the quality changes of waxy and non-waxy proso millet in different sowing dates as well as the differences in the physical and chemical properties of starch, such as starch morphological structure, crystal structure and gelatinization properties. The results showed that with the postponement of the sowing date, the total starch contents of P1 and P2 decreased by 2 % - 7.28 % and 3.26 % - 8.23 %, respectively, and the protein contents decreased by 0.1 % - 9.91 % and 2.52 % - 5.03 %, respectively. Compared with B1, B3 - B5 reduced the amylose content of P1 by 15.21 % - 26.80 %. With the postponement of the sowing date, the breakdown (BD) of P1 increased by 4.68-22.79 %, while the trough viscosity (TV) and final viscosity (FV) decreased by 2.50 % - 17.43 % and 2.58 % - 9.21 %, respectively. The peak viscosity (PV), TV, BD and FV of P2 increased by 10.33 % - 36.95 %, 9.31 % - 19.86 %, 12.68 % - 81.07 % and 5.69 % - 36.46 %, respectively, with the postponement of the sowing date. The sowing date also affected the volume distribution of proso millet grains. This study clarified the influence of sowing date on the quality of proso millet grains and the physical and chemical properties of starch, providing a theoretical basis for improving the high-yield and high-quality cultivation techniques of proso millet grains and the deep processing of products.

Effects of extrusion temperature on structure and physicochemical properties of proso millet starch

Due to its thermal stability, and high viscosity, proso millet starch has limited practical applications. Extrusion can alter the functional properties of starch by pre-gelatinization, but the specific effects of extrusion temperature on starch behavior are not clear. In this study, proso millet starch was modified using extrusion at varying temperatures (70 °C, 90 °C, 110 °C), and its structure as well as physicochemical properties were evaluated. As the extrusion temperature increased, the starch granules were gelatinized, and the particle size increased significantly. The relative crystallinity of extruded starch decreased and the short-range order was enhanced notably, but the starch still exhibited an A-type structure. Starch chains degraded, migrated, and aggregated, showing an increase in the double helix content, but there was no difference in the single helix structure with temperature. With the increase of extrusion temperature, the amorphous layer of extruded starch thickened. Moreover, the peak viscosity, breakdown viscosity and setback viscosity initially increased and then decreased, the peak temperature and enthalpy change increased. The water absorption index, water solubility and swelling power significantly decreased with increasing temperatures. The freeze-thaw stability and transparency of extruded starch decreased, and showed a downward trend with prolonged time. The above results indicate that extrusion treatment effectively modifies the thermal stability and viscosity of proso millet starch, laying a foundation for applying it different industrial applications.

Starch chain-length distributions affect the processing and digestion characteristics of proso millet starch

Starch chain-length distributions play a key role in regulating the processing and digestion characteristics of proso millet starch. Waxy proso millet starch has higher endothermic enthalpy (13.06-16.73 J/g) owing to its higher relative crystallinity (27.83%-32.04%), while nonwaxy proso millet starch has lower peak viscosity (1.0630-1.1930 Pa∙s) and stronger viscoelasticity owing to its higher amylose content (21.72%-24.34%). Non-waxy proso millet starch exhibited two different digestion phases and its resistant starch content (18.37%-20.80%) was higher than waxy proso millet starch. Correlation analysis showed proso millet starch with longer amylopectin B1 chains and more amylopectin B2 chains exhibited excellent thermal ability and retrograde resistance, whereas proso millet starch with shorter and more amylose medium/long-chains not only reduced the digestion rate and increased the resistant starch content but also exhibited stronger viscoelasticity and excellent retrogradation properties. These results could provide more insights into efficient utilization of proso millet starch.

Effects of nitrogen fertilizer application on the physicochemical properties of foxtail millet (Setaria italica L.) starch

The use of nitrogen fertilizer is a crucial agronomic practice to increase crop output and quality. This study investigated the impact of five nitrogen application levels (0, 60, 135, 210, and 285 kg N/hm2) on the physicochemical properties of foxtail millet (FM) starch. Optimal nitrogen application (210 kg N/hm2) significantly increased L*, a*, and b* values, water and oil absorption capacity, water solubility, and swelling power of starch. The number of small starch granules increased as the nitrogen application rate increased, but the granule morphology and typical A-type pattern did not change among the treatments. Nitrogen application increased the relative crystallinity and ordered structure, resulting in a higher gelatinization enthalpy. Compared to the control group (7.02 J/g), the enthalpy increased by 21.94 %, 66.38 %, 73.50 %, and 103.28 % under the nitrogen application rates, respectively. Moreover, nitrogen application greatly increased the percentage of A and B3 chains while it lowered the apparent amylose content, peak viscosity, and final viscosity. The effects of 210 and 285 kg N/hm2 treatments on the water solubility and swelling power, water and oil absorption, and light transmission of starch were greater compared to the 60 and 135 kg N/hm2 treatments. These results indicate that nitrogen fertilization significantly affects the physicochemical properties of FM starch.

Optimization of the morphological, structural, and physicochemical properties of maize starch using straw returning and nitrogen fertilization in Northeast China

The combination of straw returning and nitrogen (N) fertilization is a popular tillage mode and essential strategy for achieving stable yield and high quality. However, the optimal combination strategy and the influence of tillage mode on the morphological, crystalline, and molecular structures of maize starch remain unclear. We conducted a long-term field experiment over 7 years in Northeast China using two tillage modes, rotary tillage with straw returning (RTS) and plow tillage with straw returning (PTS), and four N application rates. The relative crystallinity, 1045/1022 cm-1 value, and B2 and B3 chains of maize starch were higher under RTS than under PTS, resulting in increased stability of starch and improvements in gelatinization enthalpy and temperature. The surface of the starch granules induced by N fertilizer was smoother than that under the N0 (0 kg N ha-1) treatment. The proportion of amylose content, solubility, swelling power, and light transmittance increased under N2 (262 kg N ha-1) treatment, along with improvement in starch pasting properties. These results suggest that RTS combined with N2 treatment can regulate the morphological, structural, and physicochemical characteristics of maize starch, providing an essential reference for improving the quality of maize starch from an agronomic point of view.

Gluten-starch microstructure analysis revealed the improvement mechanism of Triticeae on broomcorn millet (Panicum miliaceum L.)

Understanding the mechanism by which Triticeae improves the quality of broomcorn millet (BM) is key to expanding the use of this crop to address food crises and food security. This study aimed to explore the effects of Triticeae on the disulfide bonds, secondary structures, microstructure, and rheological properties of BM dough, and to investigate the potential food applications of BM. Gluten protein, intermolecular SS, and β-Sheets content of the reconstituted doughs were significantly improved compared with BM dough, which improved disorderly accumulation of starch and gluten-starch interaction in BM dough. CLSM analysis showed that broomcorn millet-common wheat (BM-CW) and broomcorn millet-durum wheat (BM-DW) also possessed larger protein areas, smaller lacunarities, and better gluten-starch interactions in the reconstituted doughs. Disulfide bonds were positively correlated with the gluten network structure, and more disulfide bonds were formed in BM-CW (3.86 μmol/g), which promoted stronger mechanical resistance in BM-CW. Therefore, the combination of BM flour with CW and DW flours had better dough elasticity and stability. Finally, a potential evaluation and optimization scheme for BM as a cooked wheaten food is proposed to improve the reference for future food security and dietary structure adjustment of residents.

Dynamic changes in microbial communities and flavor during different fermentation stages of proso millet Baijiu, a new product from Shanxi light-flavored Baijiu

Introduction

Proso millet, a high-quality fermentation material used for Chinese yellow wine production, can produce special flavored substances; however, its role in improving the flavor and altering microbial communities of light-flavored Baijiu during fermentation remain unknown. Thus, we aimed to investigate the effect of proso millet on improving the flavor of light-flavored Baijiu and altering microbial communities during different fermentation stages.

Methods

The dynamic changes in the microbial communities and flavor of proso millet (50%) + sorghum (50%) mixed fermentation samples were analyzed through intermittent sampling on days 7, 14, 21, and 28 of the fermentation process. Microbial high-throughput sequencing and the analysis of flavor characteristics were conducted through 16S DNA/ ITS amplicon sequencing and gas chromatography (multi-capillary column)-ion mobility spectrometry, respectively.

Results

Proso millet significantly changed the core flavor compound composition of traditional light-flavored Baijiu from ethyl acetate, ethyl hexanoate, ethyl hexanoate dimer, ethyl butanoate, ethyl lactate, and butyl acetate to oct-2-ene, 2-butanol, propyl propanoate, 2-pentenal, and 4-methylpentanal. The amplicon sequencing analysis revealed that the alpha diversity parameters of bacterial and fungal communities, including the Chao1, Pielou_e, Shannon, and Simpson indices, for proso millet-sorghum mixed fermentation samples were significantly higher than those for sorghum fermentation samples (p < 0.05). Of the 40 most significant microbial genera in two treatments, proso millet significantly increased the abundance of 12 bacterial and 18 fungal genera. Among the 40 most significant bacterial and fungal species, 23 bacterial species belonged to the Lactobacillus genus, whereas the 30 primary fungal species belonged to 28 different genera. The analysis of the relationship between microbial changes and the main flavor compounds of light-flavored Baijiu showed that bacteria from the Weissella, Acinetobacter, Bacteroides, Psychrobacter, Pseudarthrobacter, Lactococcus, Chloroplast, Saccharopolyspora, Psychrobacter, Saccharopolyspora, Pseudonocardiaceae, Bacteroides genera and fungi from the Thermoascus, Aspergillus, Pichia, Rhizomucor, Papiliotrema, Hyphopichia, and Mucor genera significantly inhibited the synthesis of ethyl hexanoate, ethyl butanoate, ethyl lactate ethyl lactate, and butyl acetate but increased the synthesis of ethyl acetate (p < 0.05). Moreover, these microbes exhibited a significantly greater abundance in proso millet-sorghum mixed fermentation samples than in sorghum samples. The synthesis of special flavored compounds in proso millet Baijiu was significantly positively correlated with the presence of fungi from the Rhizopus, Papiliotrema, Wickerhamomyces, Aspergillus, and Thermoascus genera but negative correlated with the presence of bacteria from the Weissella, Acinetobacter, Psychrobacter, Pseudarthrobacter, Bacteroides, and Saccharopolyspora genera. Regarding ethanol content, the low alcohol content of Fenjiu may be due to the significantly high abundance of fungi from the Psathyrella genus and bacteria from the Staphylococcus, Kroppenstedtia, Brevibacterium, and Acetobacter genera during fermentation. In summary, proso millet significantly altered the flavor of light-flavored Baijiu by inducing the formation of a special microbial community; however, it did not increase alcohol concentration.

Discussion

This study lays the foundation for future research on Baijiu fermentation. Additionally, the study findings may help improve the production efficiency and elevate the quality and flavor of the final product.

Nitrogen fertilizer affects the cooking quality and starch properties of proso millet (Panicum miliaceum L.)

Nitrogen has a critical influence on the yield and quality of proso millet. However, the exact impact of nitrogen on the cooking quality of proso millet is not clear. In this study, the cooking quality and starch properties of two proso millet varieties (waxy-Shaanxi millet [wSM] variety and non-waxy-Shaanxi millet [nSM] variety) were compared and analyzed under nitrogen fertilizer treatment (N150, 150 kg/hm2) and a control group without nitrogen application (N0, 0 kg/hm2). Compared with the N0 group, the N150 treatment significantly increased protein content, amylose levels, and total yield. Employing rapid visco analyser and differential scanning calorimetry analyses, we observed that under the N150 treatment, the peak viscosity and breakdown viscosity of proso millet powder were diminished, while the setback viscosity and enthalpy values (ΔH) increased. In addition, nitrogen treatment increased the solids content in the obtained rice soup and significantly hardened the texture of the rice. At the same time, we noticed that the absorption capacity of starch in water and oil was enhanced. These results showed that nitrogen fertilizer had significant effects on the cooking quality and starch properties of proso millet.

Starch chain-length distributions determine cooked foxtail millet texture and starch physicochemical properties

Starch chain-length distributions play an important role in controlling cereal product texture and starch physicochemical properties. Cooked foxtail millet texture and starch physicochemical properties were investigated and correlated with starch chain-length distributions in eight foxtail millet varieties. The average chain lengths of amylopectin and amylose were in the range of DP 24-25 and DP 878-1128, respectively. The percentage of short amylopectin chains (Ap1) was negatively correlated with hardness but positively correlated with adhesiveness and cohesion. Conversely, the amount of amylose intermediate chains was positively correlated with hardness but negatively correlated with adhesiveness and cohesion. Additionally, the amount of amylose long chains was negatively correlated with adhesiveness and chewiness. The relative crystallinity (RC) of starch decreased with reductions in the length of amylopectin short chains in foxtail millet. Pasting properties were mainly influenced by the relative length of amylopectin side chains and the percentage of long amylopectin branches (Ap2). Longer amylopectin long chains resulted in lower gelatinization temperature and enthalpy (ΔH). The amount of starch branched chains had important effects on the gelatinization temperature range (ΔT). These results can provide guidance for breeders and food scientists in the selection of foxtail millet with improved quality properties.

Structural analysis, nutritional evaluation, and flavor characterization of parched rice made from proso millet

This study investigated the structure and quality characteristics of hard and crispy parched rice obtained from raw proso millet through steaming, roasting, and milling. Results showed that thermal treatment disrupted the structure of samples and transformed the crystal from A-type in raw proso to V-type in parched rice. Rheological and thermodynamic analyses revealed that thermal treatment reduced the stability of parched rice. Gelatinization tests demonstrated that the parched rice was easier to gelatinize and had a lower viscosity. The digestibility of hard parched rice and crispy parched rice improved, with rapidly digestible starch content increasing by 73.62% and 76.95%, respectively, compared with that of raw proso millet. Headspace solid-phase microextraction/gas chromatography-mass spectrometry results further indicated that thermal treatment enhanced the flavor substances of parched rice. These findings demonstrated the unique properties of parched rice and supported its production and processing as a whole grain.

Comparison of the fine structure and physicochemical properties of proso millet (Panicum miliaceum L.) starch from different ecological regions

Field experiments were conducted to evaluate the morphology, granule size, fine structure, thermal properties, and pasting properties of starch from a waxy (139) and a non-waxy (297) varieties of proso millet grown in Yulin (YY) and Yangling (YL). Compared with the starches from the two varieties grown in YY, the starches from the two varieties grown in YL exhibited higher relative crystallinities, 1045/1022 cm-1 ratio, and amounts of amylopectin long branch chains (APL) but lower 1022/995 cm -1 ratio, amounts of amylopectin short branch chains (APs), and APs/APL ratios. Starches from YL also synthesized long branch-chain amylopectin to enhance intermolecular interactions and form a stable granular structure, which resulted in increased starch gelatinization temperature, enhanced shear resistance, and reduced setback viscosity. Starch from the waxy (139) variety has good application prospects in the food industry because of its high gelatinization temperature and light transmittance and low setback value, which can be ascribed to its extremely low amylose content, polydispersity index, high molecular weight, and dispersed molecular density. It may serve as a reference for applying proso millet starches in the food industry and developing breeding programs to improve starch quality.

Proso Millet (Panicum miliaceum L.) as Alternative Source of Starch and Phenolic Compounds: A Study on Twenty-Five Worldwide Accessions

Proso millet has been proposed as an effective anti-diabetic food thanks to the combined action of polyphenols and starch. This study aimed to characterize the chemical composition of twenty-five accessions, in order to enhance this cereal as an alternative to available starch for food applications or to propose new food ingredients with health benefits. Proso millet contained a high percentage of starch, reaching values of 58.51%. The amylose content showed high variability, with values ranging from 1.36 to 42.70%, and significantly higher values were recorded for the white accessions than for the colored ones. High-resistant starch content (13.41-26.07%) was also found. The HPLC-MS analysis showed the same phenolic pattern in all the samples. Cinnamic acids are the most abundant compounds and significant differences in their total content were found (0.69 to 1.35 mg/g DW), while flavonoids were only detected in trace amounts. Statistical results showed significantly higher antiradical activity in the colored accessions than in the white ones.

Biochar and Nitrogen Fertilizer Change the Quality of Waxy and Non-Waxy Broomcorn Millet (Panicum miliaceum L.) Starch

The overuse of nitrogen fertilizers has led to environmental pollution, which has prompted the widespread adoption of biochar as a soil conditioner in agricultural production. To date, there has been a lack of research on the effects of biochar and its combination with nitrogen fertilizer on the quality of broomcorn millet (Panicum miliaceum L.) starch. Thus, this study examined the physicochemical characteristics of starch in two types of broomcorn millet (waxy and non-waxy) under four different conditions, including a control group (N0), nitrogen fertilizer treatment alone (N150), biochar treatment alone (N0+B), and a combination of biochar and nitrogen fertilizer treatments (N150+B). The results showed that, in comparison to the control, all the treatments, particularly N150+B, decreased the content of amylose and gelatinization temperature and enhanced the starch transparency gel consistency and swelling power. In addition, biochar can improve the water solubility of starch and the gelatinization enthalpy. Importantly, the combination of biochar and nitrogen fertilizer increased the proportion of A-granules, final viscosity, starch content, and the average degree of amylopectin in polymerization. Thus, this research indicates that the combinations of biochar and nitrogen fertilizer result in the most significant improvement in the quality of starch produced from broomcorn millet.

Development of a Comprehensive Quality Evaluation System for Foxtail Millet from Different Ecological Regions

Foxtail millet (Setaria italica L.) is a critical grain with high nutritional value and the potential for increased production in arid and semiarid regions. The foxtail millet value chain can be upgraded only by ensuring its comprehensive quality. Thus, samples were collected from different production areas in Shanxi province, China, and compared in terms of quality traits. We established a quality evaluation system utilizing multivariate statistical analysis. The results showed that the appearance, nutritional content, and culinary value of foxtail millet produced in different ecological regions varied substantially. Different values of amino acids (DVAACs), alkali digestion values (ADVs), and total flavone content (TFC) had the highest coefficients of variation (CVs) of 50.30%, 39.75%, and 35.39%, respectively. Based on this, a comprehensive quality evaluation system for foxtail millet was established, and the quality of foxtail millet produced in the five production areas was ranked in order from highest to lowest: Dingxiang > Zezhou > Qinxian > Xingxian > Yuci. In conclusion, the ecological conditions of Xinding Basin are favorable for ensuring the comprehensive quality of foxtail millet. .

A Review on Isolation, Characterization, Modification, and Applications of Proso Millet Starch

Proso millet starch (PMS) as an unconventional and underutilized millet starch is becoming increasingly popular worldwide due to its health-promoting properties. This review summarizes research progress in the isolation, characterization, modification, and applications of PMS. PMS can be isolated from proso millet grains by acidic, alkaline, or enzymatic extraction. PMS exhibits typical A-type polymorphic diffraction patterns and shows polygonal and spherical granular structures with a granule size of 0.3-17 µm. PMS is modified by chemical, physical, and biological methods. The native and modified PMS are analyzed for swelling power, solubility, pasting properties, thermal properties, retrogradation, freeze-thaw stability, and in vitro digestibility. The improved physicochemical, structural, and functional properties and digestibility of modified PMS are discussed in terms of their suitability for specific applications. The potential applications of native and modified PMS in food and nonfood products are presented. Future prospects for research and commercial use of PMS in the food industry are also highlighted.

Effect of heat-moisture treatment on the physicochemical properties and digestibility of proso millet flour and starch

Proso millet flour (PMF) and starch (PMS) were subjected to heat-moisture treatment (HMT) at 25 % moisture content and 110 °C for 4 h. The effects of HMT on physicochemical and structural properties and in vitro digestibility of PMF and PMS were analyzed. After HMT, SEM showed aggregation and damage to the surface of starch granules, while CLSM showed proteins wrapped around the granules. The amylopectin chain length distribution (CLD) remained unchanged in PMF and PMS after HMT, indicating intact covalent bonds between glucose units. HMT decreased the swelling power, solubility, viscosity of the paste, and gelatinization enthalpy and increased the pasting temperature and gelatinization temperature of PMF and PMS. HMT changed the XRD pattern of PMF from A to A + V type starches, whereas that of PMS remained unchanged. FTIR study showed an increase in the degree of short-range molecular order of PMF and PMS after HMT. In vitro digestibility evaluation showed that the rapidly (RDS) and slowly digestible starch (SDS) contents of PMF and PMS increased, whereas the resistant starch (RS) content decreased after HMT. HMT flour and starch have suitable properties for use in a wide range of food products, from canned to frozen, as well as non-food products.

Analysis of Starch Structure and Pasting Characteristics of Millet Thick Wine during Fermentation

Starch is the main substrate in millet thick wine (MTW). In order to control the fermentation process of MTW, it is critical to monitor changes in the starch structure and physicochemical characteristics during the fermentation of MTW. In the present study, the structural characteristics of MTW starch were analyzed by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and rapid viscosity analysis (RVA). The results of SEM and CLSM showed that large starch granules in MTW swelled, developed cavities, and ruptured or even vanished with the prolongation of the fermentation time, whereas the size and shape of small starch granules barely changed, only falling off the pomegranate-seed-like aggregates. With the increase in fermentation time, the relative crystallinity of starch in MTW gradually increased. In addition, the short-range ordered structures underwent complex changes. Changes in the starch morphology and ordered structure led to an increase in the peak viscosity time and the initial gelatinization temperature. The present results reveal the beneficial effect of fermentation on MTW processing and suggest its potential applications in other millet-based fermented products.

Influence of accelerating storage of foxtail millet on the edible and cooking quality of its porridge: An insight into the structural alteration of the in-situ protein and starch and physicochemical properties

This study aimed to elucidate the effect of the accelerating storage (40 °C, 10 weeks) of foxtail millet on the edible and cooking quality of its porridge. The structural alteration of the in-situ protein and starch in foxtail millet, as well as the physicochemical properties were investigated. Both the homogeneity and palatability of millet porridge were significantly improved after 8-week storage of millet, while its proximate compositions remained unchanged. Meanwhile, the accelerating storage increased the water absorption and swelling of millet by 20 % and 22 %, respectively. The morphological studies (using the SEM, CLSM and TEM) revealed that the starch granules in the stored millet became easier to swell and melt, leading to better gelatinization with a higher coverage extension in protein bodies. FTIR results showed that the protein hydrogen bonds in the stored millet became stronger and the starch ordered degree was reduced. Compared to the native foxtail millet, the peak, trough, final, and setback viscosity of the stored sample increased by 27 %, 76 %, 115 % and 143 %, respectively, while the onset, peak, and conclusion temperature increased by 0.80, 1.10 and 0.80 °C, respectively. Besides, the G' and G″ of the stored foxtail millet were significantly higher than its native counterpart.

Effect of environment and variety on the physicochemical properties of Tartary buckwheat starch

BACKGROUND

Starch is a major nutrient in the human diet and has been widely used as an ingredient in many food and non-food applications. However, the research on the quality characteristics of Tartary buckwheat is lagging behind, and there is a lack of high-quality special varieties, which makes it difficult to become a popular food. The physicochemical properties of Tartary buckwheat starch may be affected by different environments and varieties, and the stability of planted varieties in different regions is also an important issue in current research.

RESULTS

The average amylose content and pasting properties of Dingxi Tartary buckwheat were lower, while the solubility, transparency, relative crystallinity and gelatinization enthalpy were higher compared with the other two regions, and there were significant differences between different varieties. All samples showed typical A-type structure, and the starch short-range order structure changed slightly. Amylose content, solubility, transparency, granule size distribution, pasting properties and thermal properties were significantly affected by environment and variety.

CONCLUSION

When choosing high-quality special varieties and products for processing, it contributes to select different buckwheat varieties and planting areas based on various objectives by understanding the effects of environment and varieties on the physicochemical properties of Tartary buckwheat starch. In this study, the four varieties planted in Dingxi and the two varieties in Zhaojue were easy to digest, and the differences of pasting properties and thermal properties are helpful to improve the application of Tartary buckwheat starch in the food industry. © 2023 Society of Chemical Industry.

Transcriptome analysis reveals new insights in the starch biosynthesis of non-waxy and waxy broomcorn millet (Panicum miliaceum L.)

Broomcorn millet is a popular cereal with health benefits, and its grains are rich in starch. However, the differences in the pathway and key genes involved in starch biosynthesis of waxy and non-waxy broomcorn millet grain remain unclear. Therefore, the grain and starch physicochemical index and transcriptomic analyses of two genotypes of broomcorn millet were conducted at 3, 6, 9, 12, 15, 18, and 21 days after pollination. The phenotypic and physiological results indicated that the starch synthetic process of non-waxy and waxy broomcorn millet was significantly different. The amylose, amylopectin, and total starch contents of non-waxy broomcorn millet were 1.99, 4.74, and 6.73 mg/grain, while those of waxy broomcorn millet were 0.34, 5.94, and 6.28 mg/grain, respectively. The transcriptomic analysis revealed that 106 differentially expressed genes were identified, which were mainly enriched in the "amino sugar and nucleotide sugar metabolism", "pyruvate metabolism", "galactose metabolism", and "starch and sucrose metabolism" pathways. The WGCNA suggested that a total of 31 hub genes were correlated with starch biosynthesis. These findings provide a new approach to studying the starch synthesis in broomcorn millet.

Nitrogen fertilizer affects starch synthesis to define non-waxy and waxy proso millet quality

Understanding the effect of nitrogen fertilization on the quality of proso millet is key to expanding the use of this crop to address water scarcity and food security. Therefore, this study determined the impact of nitrogen fertilization on the proso millet quality. Nitrogen fertilization significantly increased the NR and GS activities and decreased the GBSSase activity, resulting in an increase in protein content and reduction in amylose content and L*, which decreased the appearance quality. Nitrogen fertilization increased the proportion of short amylopectin chains, resulting in a more disordered carbohydrate structure, and decreased the proportion of hydrophilic functional groups, contributing to an increase in setback viscosity and decrease in pasting temperature in the waxy (w139) variety. In contrast, the non-waxy (n297) variety exhibited a larger proportion of long amylopectin chains, lower ordered structure and hydrophobic functional groups after nitrogen fertilization, which strengthened the inter- and intramolecular forces of starch colloids.

The relationship between ecological factors and commercial quality of high-quality foxtail millet "Jingu 21"

The commercial quality of foxtail millet grain (Setaria italica L.) includes appearance quality, functional quality, and cooking and eating quality, which directly determine whether consumers will purchase the product. We studied the relationship between ecological factors and commercial quality attributes of foxtail millet "Jingu 21" from twelve production areas. The results showed that altitude, latitude, and diurnal temperature range were negatively correlated with b*, total flavones content (TFC), setback (SB), consistence (CS) and pasting temperature (PTM), but positively correlated with L/B and breakdown (BD). In contrast, average temperature, average precipitation, average humidity, available nitrogen, phosphorus, and potassium had positive effects on 1,000-grain weight (KGW), b*, TFC, CS, and PTM and had a negative impact on L/B and BD. Climate factors had a greater effect on the commercial quality of foxtail millet than soil factors, and the influence of climatic factors was particularly obvious in the early and middle growth periods. The multivariate equation between ecological factors and the comprehensive score of foxtail millet commercial quality is Y = 1,159.745-4.496X₁ (altitude) + 19.529X₅ (≥10℃ effective accumulated temperature) - 166.327X₁₀ (organic matters). In conclusion, high temperature and precipitation are conducive to high quality appearance and the accumulation of functional substances, while a high diurnal temperature range and high soil nutrients are conducive to the formation of cooking and eating quality. The impact of ecological factors on foxtail millet quality is complicated and it is essential to select a cultivation site that is matched to the intended use of the foxtail millet being produced.

Nitrogenous Fertilizer Levels Affect the Physicochemical Properties of Sorghum Starch

Nitrogen is a key factor affecting sorghum growth and grain quality. This experiment was designed to investigate the physicochemical properties of sorghum starch in four sorghum varieties (Liaoza 10, Liaoza 19, Jinza 31, and Jinza 34) under four nitrogen levels: 0 kg/ha urea (N1), 300 kg/ha urea as base fertilizer (N2), 300 kg/ha urea as topdressing at the jointing stage (N3), and 450 kg/ha urea as topdressing at the jointing stage (N4). The results showed that grain size and amylose content increased with increasing nitrogen fertilizer level, peaking at N3. The peak viscosity, final viscosity, gelatinization temperature, initial temperature, final temperature, and enthalpy value increased with the nitrogenous fertilizer level, peaking at N3. The application of nitrogen fertilizer at the jointing period significantly increased the above indicators. However, excess nitrogen at the jointing period (N4) can significantly reduce the above indicators, thus changing the physicochemical properties and structure of sorghum starch. Overall, nitrogen significantly affects the structure and physicochemical properties of sorghum starch.

Comparative assessment of nutritional and functional properties of different sorghum genotypes for ensuring nutritional security in dryland agro-ecosystem

The cultivation of unique sorghum (resistant to abiotic stresses and re-recognized as healthy food) has attracted interest as an environmentally friendly minor cereal and may be a solution to food and nutritional security. However, information about how the use of selected sorghum grains affects nutritive values and its functional properties from sorghum flours is still lacking. To address this question, we selected six sorghum varieties (i.e., JinZa 34, LiaoZa 19, JinNuo 3, JiZa 127, JiNiang 2, and JiaXian) for the comprehensive analysis of the relationship among nutritional compositions, energy value contributions, and functional properties of sorghum grains. Results showed that Carr's index (CI) and angle of repose (AR) of all sorghum flours indicated good flow and compressibility properties in terms of micrometric parameters. All sorghums were considered free of tannin. Based on the scatterplot analysis, the proportions of energy contributions due to protein, fat, and carbohydrate (CHO), were highly positively correlated with protein, fat, and CHO, respectively. The significantly different flours of six sorghum varieties resulted in different functional properties. The amylose content showed a highly negative association with light transmittance and water and oil absorption capacities. In addition, amylose had a highly positive relationship with water solubility (WS) and swelling power (SP). JinNuo 3 had the highest nutritional compositions [proximate, mineral, anti-nutritional values, and amino acid (AA) profiles] and functional properties indicating that it could be used as a brewing liquor. Our findings will provide a new opportunity to cultivate sorghum as an environment friendly minor cereal crop in dryland agro-ecosystems of arid and semi-arid regions of northern China for nutritional security, agriculture processing, and non-food industry in the future.

Relationship between nitrogen fertilizer and structural, pasting and rheological properties on common buckwheat starch

Nitrogen is an essential element for the yield and quality of grain. In this study, the structural and physicochemical properties of two common buckwheat varieties under four nitrogen levels (0, 90, 180, 270 kg N ha^-1) at one location in two years were investigated. With increasing nitrogen level, the contents of moisture and amylose decreased but the contents of ash and crude protein increased. Excessive nitrogen application significantly increased the granule size, but reduced the light transmittance, water solubility, swelling power, absorption of water and oil. All the samples showed a typical A - type pattern, while high relative crystallinity and low order degree were observed under high nitrogen level. The samples under high nitrogen level had lower textural properties, pasting properties and rheological properties but higher pasting temperature and gelatinization enthalpy. These results indicated that nitrogen fertilizer significantly affected the structural and physicochemical properties of common buckwheat starch.

An optimistic future of C4 crop broomcorn millet (Panicum miliaceum L.) for food security under increasing atmospheric CO2 concentrations

Broomcorn millet, a C₄ cereal, has better tolerance to environmental stresses. Although elevated atmospheric CO₂ concentration has led to grain nutrition reduction in most staple crops, studies evaluating its effects on broomcorn millet are still scarce. The yield, nutritional quality and metabolites of broomcorn millet were investigated under ambient CO₂ (aCO₂, 400 µmol mol^-1) and elevated CO₂ (eCO₂, aCO₂+ 200 µmol mol^-1) for three years using open-top chambers (OTC). The results showed that the yield of broomcorn millet was markedly increased under eCO₂ compared with aCO₂. On average, eCO₂ significantly increased the concentration of Mg (27.3%), Mn (14.6%), and B (21.2%) over three years, whereas it did not affect the concentration of P, K, Fe, Ca, Cu or Zn. Protein content was significantly decreased, whereas starch and oil concentrations were not changed by eCO₂. With the greater increase in grain yield, eCO₂ induced increase in the grain accumulations of P (23.87%), K (29.5%), Mn (40.08%), Ca (22.58%), Mg (51.31%), Zn (40.95%), B (48.54%), starch (16.96%) and oil (28.37%) on average for three years. Flavonoids such as kaempferol, apigenin, eriodictyol, luteolin, and chrysoeriol were accumulated under eCO₂. The reduction in L-glutamine and L-lysine metabolites, which were the most representative amino acid in grain proteins, led to a reduction of protein concentration under eCO₂. Broomcorn millet has more desirable nutritional traits for combating hidden hunger. This may potentially be useful for breeding more nutritious plants in the era of climate change.

Integrated Starches and Physicochemical Characterization of Sorghum Cultivars for an Efficient and Sustainable Intercropping Model

Sorghum has good adaptation to drought tolerance and can be successfully cultivated on marginal lands with low input cost. Starch is used in many foods and nonfood industrial applications and as a renewable energy resource. Sorghum starches with different amylose contents affect the different physicochemical properties. In this study, we isolated starches from six sorghum varieties (i.e., Jinza 34, Liaoza 19, Jinnuo 3, Jiza 127, Jiniang 2, and Jiaxian) and investigated them in terms of their chemical compositions and physicochemical properties. All the starch granules had regular polygonal round shapes and showed the characteristic “Maltese cross”. These six sorghum starches showed an A-type diffraction pattern. The highest amylose content of starch in Jinza 127 was 26.90%. Jiaxian had a higher water solubility at 30, 70, and 90 °C. From the flow cytometry analysis based on six sorghum starch granules, Liaoza 19 had a larger and more complex granules (particle percentage (P1) = 66.5%). The Jinza 34 starch had higher peak (4994.00 mPa∙s) and breakdown viscosity (4013.50 mPa∙s) and lower trough viscosity (973.50 mPa∙s). Jinnuo 3 had higher onset temperature, peak temperature, conclusion temperature, gelatinization enthalpy, and gelatinization range. The principal component analysis and hierarchical cluster analysis based on classification of different sorghum starches showed that Jiniang 2 and Jinnuo 3 had similar physicochemical properties and most divergent starches, respectively. Our result provides useful information not only on the use of sorghum starches in food and non-food industries but for the great potential of sorghum-based intercropping systems in maintaining agricultural sustainability.

Endogenous bioactive gibberellin/abscisic acids and enzyme activity synergistically promote the phytoremediation of alkaline soil by broomcorn millet (Panicum miliaceum L.)

Broomcorn millet (Panicum miliaceum L.), an important food crop, grows in arid and semi-arid areas that face soil saline-alkalization. To date, no studies have investigated the mechanisms by which broomcorn millet seeds respond to and tolerate alkali stress. In this study, six broomcorn millet genotypes (B102, B220, B269, B279, B289, and B297) were selected to explore the physiological and molecular mechanisms of alkali stress at the germination stage. The results showed that alkali stress delayed the germination of broomcorn millet, and α-amylase activity was positively correlated with the germination rate. After alkali stress, the genotypes with lower alkali damage rates exhibited stronger antioxidant defenses. Real-time polymerase chain reaction analysis showed that alkali stress downregulated gibberellic acid (GA) synthesis genes but upregulated GA inactivation and abscisic acid (ABA) synthesis genes. Similarly, seeds displayed lower GA concentrations and higher ABA concentrations after alkali stress. Therefore, the ratios of various GAs/ABA decreased within the range of 35.77% to approximately 96.45%. Additionally, genotypes associated with lower alkali damage rates had higher GA/ABA ratios. These findings indicate that the alkali tolerance of broomcorn millet at the germination stage may be attributed to higher GA/ABA ratios, higher α-amylase activity, and stronger antioxidant defense, which synergistically resist alkali stress. This study will contribute to molecular breeding aiming to enhance alkali-tolerance and restoration of alkaline soils.

Analysis of synthesis, accumulation and physicochemical properties of Tartary buckwheat starches affected by nitrogen fertilizer

Nitrogen fertilizer is a crucial factor affecting the growth and grain quality of Tartary buckwheat. This study was to investigate the synthesis, accumulation, and physicochemical properties of Tartary buckwheat starches under four nitrogen levels (0, 90, 180, 270 kg N ha^-1). The results showed that activities of four key enzymes, starch contents all first increased and then decreased with increasing nitrogen levels, and peaked at 180 kg N ha^-1. All the starches showed typical A-type, while higher nitrogen levels significantly increased the relative crystallinity. The viscosities significantly decreased, onset, peak, and conclusion first decreased and then increased, while pasting temperature and gelatinization enthalpy increased with increasing nitrogen levels. Nitrogen fertilizer and year had significant effects on the synthesis, accumulation and physicochemical properties of Tartary buckwheat starch, and the nitrogen level of 180 kg N ha^-1 was more suitable for planting in the northern area of the Loess Plateau.

Proteomics characterization nitrogen fertilizer promotes the starch synthesis and metabolism and amino acid biosynthesis in common buckwheat

Nitrogen (N) affects common buckwheat quality by affecting starch and amino acids (AAs) content, but its molecular mechanism is still unclear. We selected two common buckwheat varieties with high and low starch content, and designed two treatments with 180 and 0 kg N/ha. Application of high-N led to significant increases in starch, amylose and amylopectin content. Of 1337 differentially expressed proteins (DEPs) induced by high-N conditions. 472DEPs were significantly upregulated and 176DEPs downregulated for Xinong9976. 239DEPs were significantly upregulated and 126DEPs downregulated for Beizaosheng. The six alpha-glucan phosphorylases, three alpha-amylases, one granule-bound starch synthase 1 and one sucrose synthase exhibited higher expression at the 180 kg N/ha than at the 0 kg N/ha. In addition, high-N application promoted arginine, leucine, isoleucine and valine biosynthesis. This study revealed the effect of N on the starch and AA content of common buckwheat and its mechanism. The crucial proteins identified may develop the quality of common buckwheat.

Proso-millet starch: Properties, functionality, and applications

Previously proso-millet, considered an underutilized cereal, has drawn considerable attention due to health benefits like good nutritional profile, low glycemic index, and gluten-free. The present review discusses starch extractability, structural characteristics, morphology, and physicochemical properties. Starch properties mainly depend on the amylose and amylopectin composition and distribution of brained chains. A very diverse starch structure and morphology were observed among the waxy and non-waxy cultivars. The amylose content ranged from 0.75 to 28.3% in many varieties, but exceptionally Hongmeizi variety showed a 32.3% as per the reported evidence. There are a positive correlation between the amylose content and cooking quality, thermal and pasting properties. The size and shape of smallest to largest starch granules varied between 0.3 and 17 μm and round to polygonal, respectively. The non-waxy starch varieties of proso-millet are widely used in food processing due to high resistance to swelling during heat treatment. Few food applications of proso-millet are bakery products like gluten-free bread, porridge, pasta, ready-to-eat breakfast cereals, infant foods, and distilleries. We can conclude that proso millet is an alternative to existing starch for its quality characteristics and provides insight to many food processing industries.

Codon usage pattern and genetic diversity in chloroplast genomes of Panicum species

Exploring the molecular identities and the genetic diversity of a plant species is crucial in figuring out the evolutionary pressure of genes as well as in molecular breeding application. Nineteen chloroplast genomes of Panicum species in the National Center for Biotechnology Information database were downloaded and analyzed. The base composition, the effective number of codons, the relative synonymous codon usage, the codon bias index and the codon adaptation index of all genes in all chloroplast genomes, as well as the correlation coefficient among them, were calculated and discussed. The correspondence analysis and the clustering characteristics among nineteen genomes base on the relative synonymous codon usage values of nineteen chloroplast genomes were calculated and analyzed. In order to figuring out the evolutionary diversity of certain genes, the codon usage pattern of forty-one typical genes were separately counted and compared. Summations of their standard deviations were considered to evaluate their genetic diversities. The results of codon usage pattern showed that all genes were obvious AU-rich ones in chloroplast genomes of Panicum species, revealing that the natural selection was the main factor that influenced their evolutionary process. The correspondence and clustering analysis among nineteen chloroplast genomes showed that the overall evolutionary differences among them were not significant. However, the analysis on the genetic diversity of tyical genes showed that the degrees of diversity are different, and that the shorter sequences are more prone to instability. These findings would improve our understanding on the evolution of chloroplast genomes of Panicum species and be useful for further study on their evolutionary phenomenon.

New Type of Food Processing Material: The Crystal Structure and Functional Properties of Waxy and Non-Waxy Proso Millet Resistant Starches

Resistant starch (RS) is widely used in the food industry because of its ability to regulate and protect the small intestine, but their distinct effects on the structural and functional properties of waxy and non-waxy proso millet starches are not completely understood. The crystalline structure and physicochemical properties of waxy and non-waxy proso millets' starch samples were analyzed after heat-moisture treatment (HMT). The analysis revealed significant differences between the RS of waxy and non-waxy proso millets. The crystal type of proso millets' starch changed from type A to type B + V. The relative crystallinity of the RS of waxy proso millet was better than that of non-waxy proso millet. The gelatinization temperature and thermal stability of RS significantly increased, and the pasting temperature (PTM) of the RS of waxy proso millet was the highest. The water solubility and swelling power of the RS in proso millet decreased, and the viscoelasticity improved. The correlation between the short-range ordered structure of RS and ΔH, and gelatinization properties has a stronger correlation. This study provides practical information for improving the nutritional benefits of waxy and non-waxy proso millet in food applications.

Liquor Flavour Is Associated With the Physicochemical Property and Microbial Diversity of Fermented Grains in Waxy and Non-waxy Sorghum (Sorghum bicolor) During Fermentation

The fermentation process of Chinese Xifeng liquor involves numerous microbes. However, the sources of microbes in fermented grain and the link between liquor flavour and physicochemical properties and microbial diversity during fermentation still remain unknown. Herein, two waxy (JiNiang 2 [JN-2] and JinNuo 3 [JN-3]) and four non-waxy (JiZa 127 [JZ-127], JinZa 34 [JZ-34], LiaoZa 19 [LZ-19], and JiaXian [JX]) sorghum varieties were selected for the comprehensive analysis of the relationship between liquor flavour and the physicochemical properties and microbial diversity of fermented grains. Results showed that ethyl acetate was the main flavour component of JZ-127, JZ-34, and JX, whereas ethyl lactate was mainly detected in JN-2, JN-3, and LZ-19. Ethyl lactate accounted for half of the ethyl acetate content, and JX exhibited a higher liquor yield than the other sorghum varieties. The fermented grains of waxy sorghum presented higher temperature and reducing sugar contents but lower moisture and starch contents than their non-waxy counterparts during fermentation. We selected JN-3 and JX sorghum varieties to further investigate the microbial changes in the fermented grains. The bacterial diversity gradually reduced, whereas the fungal diversity showed nearly no change in either JN-3 or JX. Lactobacillus was the most abundant bacterial genus, and its level rapidly increased during fermentation. The abundance of Lactobacillus accounted for the total proportion of bacteria in JX, and it was higher than that in JN-3. Saccharomyces was the most abundant fungal genus in JX, but its abundance accounted for a small proportion of fungi in JN-3. Four esters and five alcohols were significantly positively related to Proteobacteria, Bacteroidetes, and Actinobacteria; Alphaproteobacteria, Actinobacteria, and Bacteroidia; Bacillales, Bacteroidales, and Rhodospirillales; and Acetobacter, Pediococcus, and Prevotella_7. This positive relation is in contrast with that observed for Firmicutes, Bacilli, Lactobacillales, and Lactobacillus. Meanwhile, Aspergillus was the only fungal microorganism that showed a significantly negative relation with such compounds (except for butanol and isopentanol). These findings will help in understanding the fermentation mechanism and flavour formation of fermented Xifeng liquor.

Improving the Functionality of Proso Millet Protein and Its Potential as a Functional Food Ingredient by Applying Nitrogen Fertiliser

Nitrogen is required for proso millet growth and has a critical influence on yield and quality. However, the effect of nitrogen fertilisation on proso millet protein properties remains unclear. This study aimed to investigate how nitrogen fertiliser treatment (180 kg/hm²) affects the structural and functional properties of proso millet protein. In comparison with the control group (N0), nitrogen fertiliser treatment loosened the dense structure of the protein and presented a larger particle size. Nitrogen treatment did not change the main subunit composition, and β-sheet and α-helix were the main secondary structures of proso millet protein based on Fourier transform infrared spectroscopy. In addition, nitrogen fertiliser treatment improved the content of hydrophobic amino acids and β-sheet proportion from proso millet protein, and high water/oil absorption capacity and thermal stability was observed, but the solubility, emulsion stability and foaming properties from proso millet protein decreased. Proso millet proteins exhibited high amino acid content and good functional properties, including solubility, foaming capacity and emulsifying properties, especially the w139 variety. Results show that proso millet protein has great potential for food applications. The above results provide useful information for the food industry to determine emerging gluten-free protein resources.

Study on metabolic variation in whole grains of four proso millet varieties reveals metabolites important for antioxidant properties and quality traits

Proso millet (Panicum miliaceum L.) is a minor cereal crop that has been considered as health-promoting food. Little information is available however, about the metabolic basis of nutritional values of proso millet. In this study, using a UHPLC-QqQ-MS/MS-based metabolomics approach, we compared the metabolomes of whole grains from four proso millet varieties with different bran color, namely White, Black, Gray and Red. In total, 672 metabolites were identified, among which 121, 116 and 148 metabolites showed differential accumulation in the three comparison groups (White vs. Black/Gray/Red). The results demonstrated the main pathways that were differentially activated included: tryptophan metabolism, flavonoid, isoflavonoid, flavone, and flavonol biosynthesis. Considerable difference between varieties was observed in accumulation of phenolic acids and flavonoids, which might lead to difference in antioxidant activities. The results of this study provide useful information for further investigation of proso millet food chemistry and for sufficient utilization of this special crop.

Diverse effects of nitrogen fertilizer on the structural, pasting, and thermal properties of common buckwheat starch

At present, the yield of common buckwheat, which is mainly grown in northern Shaanxi of China, is low and the grain quality is poor. Nitrogen is an important nutrient for the growth of common buckwheat, and appropriate nitrogen application can improve the grain quality. Nitrogen fertilizer could alter the starch granule morphology shapes and the granule size distribution. With increasing nitrogen levels, branch number, flower clusters number, grain number per plant, contents of protein and fat, size distribution of "C" granules, and percentages of light transmittance significantly increased, whereas amylose content and retrogradation decreased. All the samples displayed typical A-type X-ray diffraction patterns. Starch showed higher pasting temperature and gelatinization enthalpy but lower trough and final viscosities under high nitrogen levels. These results suggested N₂ treatment was more suitable for common buckwheat growth, principal components and correlation analysis revealed that nitrogen fertilizer significantly affected the physicochemical properties of common buckwheat starches.

Capitalizing on a double crop: Recent advances in proso millet's transition to a food crop

Across the globe, strategies to adapt food production to a changing climate as well as to unforeseen events (such as a pandemic) are needed, for example, if farmers miss planting times due to abnormal weather patterns or harvests are lost. Such food security considerations represent reasons for why proso millet deserves a more prominent place at the table. It has one of the shortest growing seasons and water requirements among cereals and is already grown in rotation with other crops, for example, in the American Midwest. Yet, most consumers in the Western world are unfamiliar with it, which limits its market potential. Introducing proso millet to consumers requires development of products with acceptable textural and sensory attributes as well as convincing selling points. These can be found in its nutritional profile, as it is a gluten-free "ancient" grain and millet-based products frequently have low glycemic indices. This review presents a synthesis of recent studies that utilized processing strategies to advance proso millet functionality. Results are put into the context of the most frequently addressed compositional and functional attributes, organized in clusters. Diversity across varieties in amylose to amylopectin ratios presents an opportunity to utilize proso millet for foods with specific pasting requirements, as in bread versus pasta. Hydrothermal or pressure treatments may further adapt its functionality for baked goods. Bitterness remains an unsolved issue, even when decorticated material is used. In addition, heating dramatically lowers in vitro protein digestibility, whereas starch digestibility appears to be matrix dependent (more than raw material dependent).