Multi-Scale Structures and Functional Properties of Quinoa Starch Extracted by Alkali, Wet-Milling, and Enzymatic Methods

Effects of isolation methods on physicochemical properties of defatted starch from the acorn (Quercus brantii)

This study explores the innovative combined effects of alkaline isolation with ultrasound pretreatment on the physicochemical properties of acorn (Quercus brantii) starch. The optimal pH for maximizing the yield of alkaline-isolated acorn starch (AAS) was determined, followed by comparison with alkaline-isolated defatted acorn starch (ADAS), ultrasound-pretreated acorn starch (UAS), and ultrasound-pretreated defatted acorn starch (UDAS). The results demonstrated substantial improvements in yield and purity, with the highest yield (68.97 ± 0.16 %) achieved at pH 9. ADAS showed high purity, with protein and fat contents of 1.82 ± 0.07 % and 0.025 ± 0.02 %, respectively. UDAS exhibited superior swelling power, solubility, and turbidity, indicating enhanced functional properties. Scanning Electron Microscopy (SEM) revealed variations in granule sizes across treatments, from 12.42 μm (ADAS) to 10.72 μm (UDAS). X-ray diffraction analysis showed C-type patterns with crystallinity ranging from 31.25 % (ADAS) to 26 % (UAS). Thermal analysis demonstrated UDAS had the highest peak viscosity and lowest thermal parameters. Texture analysis indicated that AAS formed a softer gel, while ADAS displayed greater hardness and gumminess. These findings highlight the effectiveness of combining alkaline isolation with ultrasound pretreatment to improve acorn starch quality for sustainable applications in food and biotechnology.

Green Starch Modification Using Citric Acid: Quinoa, Chickpea, and Cassava Starches

Dietary fibre deficiency has been associated with various global health challenges. Starch, as a main component of many staple foods, is typically very low in fibre content. The primary aim of this research was to increase the dietary fibre and alter the physicochemical properties of some common and emerging starches (cassava, quinoa, and chickpea starch) using eco-friendly modifications. Citric acid, a safe, natural, and environmentally friendly cross-linking agent, was employed for this purpose. Starch samples were treated with 30% citric acid and dry-heated at 130 °C for 5 h. This process resulted in relatively high degrees of substitution: 0.124 for cassava, 0.117 for quinoa, and 0.112 for chickpea starches. The modification successfully produced rich sources of dietary fibre suitable for food applications. It also reduced water interactions, pasting properties, and crystallinity. The highest reduction in swelling power and solubility was observed in quinoa starch (-67.34% and -82.10%, respectively), while the lowest values were obtained for cassava starch (-35.39% and -44.22%). All starches retained their granular integrity; however, they lost birefringence and Maltese crosses and showed some erosions on the granule surfaces. The citrate starches produced in this research offer thermally stable starch suitable for various food applications.

Unveiling the nutritional spectrum: A comprehensive analysis of protein quality and antinutritional factors in three varieties of quinoa (Chenopodium quinoa Wild)

Quinoa (Chenopodium quinoa) is renowned for its high protein content and balanced amino acid profile. Despite promising protein characteristics, plant-based sources usually possess antinutritional factors (ANFs). This study aimed to analyze the nutritional and ANFs composition of three quinoa varieties (Black, Yellow, and Red), and assessed the protein quality. Among these varieties, Black quinoa showed the highest protein content (20.90 g/100 g) and total dietary fiber (TDF) (22.97 g/100 g). In contrast, Red quinoa exhibited the highest concentration of phenolic compounds (338.9 mg/100 g). The predominant ANFs identified included oxalates (ranging from 396.9 to 715.2 mg/100 g), saponins (83.27-96.82 g/100 g), and trypsin inhibitors (0.35-0.46 TUI/100 g). All three varieties showed similar in vitro protein digestibility (IVPD) (> 76.9 %), while Black quinoa exhibited the highest protein quality. In conclusion to ensure reduction of ANFs, processing methods are necessary in order to fully benefit from the high protein and nutritional value of quinoa.

Variations in the Impact of Gingerols' Conversion to Shogaols on the Properties of Corn Starch with Different Amylose Contents

The polyphenol-starch complex has become a hot research topic since it is evident that this modification method can alter the physicochemical properties of starch as well as improve its nutritional value. This work aimed to evaluate the effect of ginger polyphenol gingerols (GNs) and shogaols (SNs) on the structure of starch with different amylose content (WCS, CS, G56, G80). Textural and rheological results indicated that GNs and SNs had more pronounced inhibitory retrogradation effects for relative low-level amylose starches (WCS and CS) compared to relative high-level amylose starches (G56 and G80). GNs and SNs improved the freeze-thaw stability of starch gels. FT-IR and XRD results revealed that GNs and SNs decreased the (short- and long-range) ordered structure of starches through a non-covalent interaction. Moreover, DSC results proved that the gelatinisation temperature of CS/G56/G80 significantly increased, and the enthalpy (ΔH) decreased by the incorporation of GNs and SNs. Overall, this in-depth study is beneficial in providing valuable pathways for starch-polyphenol interactions to improve the quality of starchy foods.

Investigating the Effects of Acid Hydrolysis on Physicochemical Properties of Quinoa and Faba Bean Starches as Compared to Cassava Starch

In response to the growing demand for high-quality food ingredients, starches from underutilised sources like quinoa and faba bean are gaining attention due to their unique properties and high tolerance to adverse environmental conditions. Acid hydrolysis is a well-established chemical method for producing modified starch with improved solubility, lower gelatinisation temperature, and reduced pasting viscosity. However, various outcomes can be achieved depending on the type of starch and modification conditions. This study comparatively investigated the effects of acid hydrolysis on the functional and physicochemical properties of emerging starches from quinoa and faba bean, with cassava starch serving as a reference from a leading source. The results demonstrated increased dietary fibre content across all three starches, with faba bean starch showing the most significant rise. Acid treatment also enhanced the crystallinity of the starches, with faba bean starch exhibiting the highest increase in relative crystallinity, which led to a shift towards higher temperatures in their thermal properties. Additionally, water solubility and oil adsorption capacity increased, while swelling power decreased following acid treatment. The acid treatment reduced the pasting properties of all samples, indicating that the modified starches were more resistant to heating and shearing in the rapid visco analyser. While quinoa starch gel remained soft after acid hydrolysis, the gel strength of cassava and faba bean starches improved significantly, making them suitable as plant-based gelling agents.

Acid Hydrolysis of Quinoa Starch to Stabilize High Internal Phase Emulsion Gels

Starch nanocrystals (SNCs) to stabilize high internal phase emulsions (HIPEs) always suffer low production efficiency from acid hydrolysis. Due to its small granule size, Quinoa starch (QS) was selected to produce SNCs as a function of acid hydrolysis time (0-4 days), and their structural changes and potential application as HIPEs' stabilizers were further explored. With increasing the acid hydrolysis time from 1 day to 4 days, the yield of QS nanocrystals decreased from 30.4% to 10.8%, with the corresponding degree of hydrolysis increasing from 51.2% to 87.8%. The occurrence of QS nanocrystals was evidenced from the Tyndall effect and scanning electron microscopy with particle size distribution. The relative crystallinity of QS subjected to different hydrolysis times (0-4 days) increased from 22.27% to 26.18%. When the acid hydrolysis time of QS was 3 and 4 days, their HIPEs showed self-standing after inversion, known as high internal phase emulsion gels (HIPE gels), closely related to their densely packed interfacial architecture around oil droplets, seen on an optical microscope, and relatively high apparent viscosity. This study could provide a theoretical guidance for the efficient production and novel emulsification of SNCs from QS to HIPE gels.

Physiochemical characterization and ameliorative effect of rice resistant starch modified by heat-stable α-amylase and glucoamylase on the gut microbial community in T2DM mice

In the presented study, natural rice containing high resistant starch content was used as a raw material to produce rice resistant starch (RRS) through enzymatic hydrolysis with heat-stable α-amylase and glucoamylase. The chemical composition, structural characteristics and in vitro glycemic index (GI) of RRS were evaluated. The effects of RRS at different doses on the body weight, serum biochemical levels, pathological indexes, production of short-chain fatty acids (SCFAs) in the gut and the intestinal microbial composition in T2DM mice were investigated. The results of physiochemical characterization indicated that, relative to rice flour, RRS mainly comprising resistant starch had higher crystallinity (25.85%) and a more stable structure, which contributed to its lower digestibility and decreased GI in vitro. Compared with the model control group, 1 g per kg BW and 2 g per kg BW oral gavage dosages of RRS effectively enhanced the SCFA productivity in the T2DM mouse gut, as well as alleviating T2DM symptoms, involving an increase in body weight, reduction in fasting blood glucose, total cholesterol, triglyceride, low-density lipoprotein cholesterol, alanine transaminase and aspartate aminotransferase, and an increase in serum insulin and high-density lipoprotein cholesterol. Besides, 1 g per kg BW and 2 g per kg BW dosages of RRS mitigated T2DM-induced pancreas damage. Furthermore, up-regulation in the abundance of probiotics (Lactobacillus, Ruminococcus, etc.) and down-regulation in the number of harmful bacteria (Desulfovibrio, Prevotella, etc.) were observed in all RRS-treated groups. In summary, this work suggested that RRS prepared using heat-stable α-amylase and glucoamylase could be a potential functional component for amelioration of T2DM applied in the fields of food and pharmaceutics.

Physicochemical properties and in vitro digestibility of proso millet starch modified by heat-moisture treatment and annealing processing

Heat-moisture treatment (HMT) and annealing (ANN) were applied to modify the proso millet starch, and then the physicochemical properties as well as the in vitro digestion of the modified starch were investigated systematically. Results indicated that HMT and ANN did not change the typical A-type crystallinity. However, both processes cause cracks and dents on the surface of the granule. The gelatinization temperature increased while peak viscosity value, relative crystallinity and gelatinization enthalpy of proso millet starch decreased significantly after HTM and ANN. Meanwhile, a remarkable increase of the slowly digestible starch(SDS) and resistant starch(RS) content was noticed after HTM and ANN modification (the highest content of SDS and RS after HTM and ANN were 9.52 ± 0.82 %, 12.03 ± 1.36 % and 12.15 ± 0.89 %, 8.75 ± 1.63 %, respectively). Those results indicated that the ANN and HMT processes could modify the physicochemical properties and in vitro digestion of proso millet starch efficiently and showed potential application to produce healthy starch food with lower digestion.