Functional properties of sweet potato flour and its role in product development: a review

Reclaiming Agriceuticals from Sweetpotato (Ipomoea batatas [L.] Lam.) By-Products

Sweetpotato (SP, Ipomoea batatas [L.] Lam.) is a globally significant food crop known for its high nutritional and functional values. Although the contents and compositions of bioactive constituents vary among SP varieties, sweetpotato by-products (SPBs), including aerial parts, storage root peels, and wastes generated from starch processing, are considered as excellent sources of polyphenols (e.g., chlorogenic acid, caffeoylquinic acid, and dicaffeoylquinic acid), lutein, functional carbohydrates (e.g., pectin, polysaccharides, and resin glycosides) or proteins (e.g., polyphenol oxidase, β-amylase, and sporamins). This review summarises the health benefits of these ingredients specifically derived from SPBs in vitro and/or in vivo, such as anti-obesity, anti-cancer, antioxidant, cardioprotective, and anti-diabetic, evidencing their potential to regenerate value-added bio-products in the fields of food and nutraceutical. Accordingly, conventional and novel technologies have been developed and sometimes combined for the pretreatment and extraction processes aimed at optimising the recovery efficiency of bioactive ingredients from SPBs while ensuring sustainability. However, so far, advanced extraction technologies have not been extensively applied for recovering bioactive compounds from SPBs except for SP leaves. Furthermore, the incorporation of reclaimed bioactive ingredients from SPBs into foods or other healthcare products remains limited. This review also briefly discusses current challenges faced by the SPB recycling industry while suggesting that more efforts should be made to facilitate the transition from scientific advances to commercialisation for reutilising and valorising SPBs.

Effects of Ugali Maize Flour Fortification with Chia Seeds (Salvia hispanica L.) on Its Physico-Chemical Properties and Consumer Acceptability

The study investigated the effect of incorporating whole chia seeds (WCS) and defatted chia seed flour (DCF) into whole maize meal for ugali preparation. Both were incorporated at substitution levels of 3%, 6%, and 9% separately, and the resulting treatments subjected to laboratory analysis. In addition, ugali samples were prepared from all the resulting flour formulations and subjected to consumer acceptability assessment. Incorporation of both DCF and WCS resulted in increased water absorption capacity (ranging from 0.78 to 0.98 g/mL), swelling index (ranging from 0.15 to 3.25 mL/g), and swelling capacity (ranging from 2.46 to 5.74 g/g). WCS decreased the bulk density and oil absorption capacity. DCF, however, resulted in an increase in bulk density and oil absorption capacity. Both DCF and WCS lowered the lightness (L*) of the products. Proximate composition ranged from 4.78 to 7.46% for crude fat, 7.22% to 9.16% for crude protein, and 1.74 to 4.27% for crude fiber. The obtained results show the potential of chia seeds as a good fortificant of maize flour since it resulted in nutritionally superior products (crude ash, crude protein, crude fat, and energy value) when compared to control. The freshly prepared ugali samples were generally acceptable to the panelists up to 9% WCS and 6% DCF substitution levels.

Effect of replacing durum wheat semolina with Tenebrio molitor larvae powder on the techno-functional properties of the binary blends

Tenebrio molitor (TM) larvae, due to their high nutritional value, are gaining growing attention in food and feed sectors. Although few studies dealt with wheat-based products functionalized with TM larvae powder, there is a lack of comprehensive characterization of the raw materials to optimize the formulations for end-product recommendation. This study aimed at investigating the effects of partial replacement of durum wheat semolina with increasing amounts of TM larvae powder (5-30%) on the techno-functional properties of the binary blends. Color, granulometry, hydration properties, pasting characteristics, spectral characteristics (FTIR), reducing sugar content, and bioactivity in terms of total phenolic content (TPC) and antioxidant activity (FRAP, DPPH, ABTS) were assessed in the resulting blends. The increasing insect powder decreased the lightness (L*) and yellowness (b*) but increased the redness (a*) of the samples. In turn, the addition of insect powder did not negatively alter the hydration properties, which were comparable to those detected for semolina. Higher amounts of insect powder led to increased protein and lipid contents, as corroborated by the FTIR spectra, and decreased pasting parameters, with stronger starch granule stability detected when 20% and 30% of insect powder were added to the formulation. Significant increases in TPC and antioxidant activity were observed with increasing amount of insect powder (up to 87%, 78%, 2-fold, 67%, for TPC, FRAP, DPPH, and ABTS, respectively, compared to semolina). Therefore, these promising results have highlighted the possibility of using TM larvae powder as an unconventional ingredient for wheat-based products, by enhancing the nutritional and health-promoting values.

Nutritional contributions and processability of pasta made from climate-smart, sustainable crops: A critical review

Total or partial replacement of traditional durum wheat semolina (DWS) by alternative flours, such as legumes or wholegrain cereals in pasta improves their nutritional quality and can make them interesting vector for fortification. Climate-smart gluten-free (C-GF) flours, such as legumes (bambara groundnut, chickpea, cowpea, faba bean, and pigeon pea), some cereals (amaranth, teff, millet, and sorghum), and tubers (cassava and orange fleshed sweet potato), are of high interest to face ecological transition and develop sustainable food systems. In this review, an overview and a critical analysis of their nutritional potential for pasta production and processing conditions are undertaken. Special emphasis is given to understanding the influence of formulation and processing on techno-functional and nutritional (starch and protein digestibility) properties. Globally C-GF flours improve pasta protein quantity and quality, fibers, and micronutrients contents while keeping a low glycemic index and increasing protein digestibility. However, their use introduces anti-nutritional factors and could lead to the alteration of their techno-functional properties (higher cooking losses, lower firmness, and variability in color in comparison to classical DWS pasta). Nevertheless, these alternative pasta remain more interesting in terms of nutritional and techno-functional quality than traditional maize and rice-based gluten free pasta.

Development and properties of biodegradable film from peach palm (Bactris gasipaes)

Formulations of biodegradable films using macrocarpa peach palm flour (low amylose starch), chitosan and glycerol, were developed and the effects of the drying temperature on films by assessing their physicochemical, mechanical, barrier, optical, structural, antioxidant properties, and the biodegradability in soil were evaluated. Chitosan enhanced the mechanical properties of the films, but they showed no antimicrobial activity against the tested food-borne pathogens, except for Listeria monocytogenes, for which the inhibition zone was from 0.1 to 0.6 cm. Films with higher concentrations of peach palm flour are opaquer, with better antioxidant characteristics and content of phenolic compounds compared to films made with lower concentrations of flour. The films presented a yellowish color because of the carotenoids found in peach palm flour, 29.63 μg 100 g-1, and exhibited a C-type X-ray pattern, characteristic peak of materials where amylose and amylopectin are present. After 15 days in soil, the films lost 30% of their initial weight. Therefore, these results suggest that the development of films as food preservative is a promising field and that the material used in the study are suitable for their formulation.

Combination of enzymatically hydrolyzed potato powder with skimmed milk powder on the quality improvements of yogurt during refrigeration storage

This study aimed to prepare a stirred type of fat-free yogurt from enzymatically hydrolyzed potato powder (EHPP) and skimmed milk powder (SMP) without changing its quality and consumer acceptance. The yogurt formulations prepared contained different amount of EHPP 0, 10, 25 and 50% and were stored for 28 days at 4 °C and observed that with increasing substitution ratio, acid production was increased while the viability of lactic acid bacteria was decreased after 28 days of storage at 4 °C. The antioxidant activities (2-Diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) of the yogurt were increased with increasing EHPP over the storage period. The yogurt formulations having 25 to 50% EHPP has the highest DPPH free radical scavenging activity and FRAP values. Water holding capacity (WHC) was decreased over the storage period with 25% EHPP. The hardness, adhesiveness and gumminess were decreased while no significant change was found in springiness with EHPP addition over the storage period. The rheological analysis showed an elastic behavior of yogurt gels with EHPP supplementation. The sensory results of yogurt containing 25% EHPP have the highest values of taste and acceptance. Yogurt in combination with EHPP and SMP has the higher levels of WHC than non-supplemented yogurt and better stability was recorded during storage.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05737-9.

Physicochemical, Nutritional, and Antioxidant Properties in Seven Sweet Potato Flours

Sweet potato flour is a key ingredient for the production of new food products worldwide, which imparts desired properties, nutritional value, antioxidants, and natural color to processed foods. However, little information regarding the functional properties of the sweet potato flour is available. In this study, the genetic diversity in the physiochemical, nutritional, and antioxidant properties of wholemeal flour from seven sweet potato varieties was investigated. The total phenolic content (TPC) of the free and bound fractions ranged from 13.85 to 90.74 mg gallic acid equivalent (GAE)/100 g and from 5.07 to 24.29 mg GAE/100 g, respectively. The average protein content of sweet potato was 5.41 g/100 g ranging from 3.40 to 8.60 g/100 g DW. The total amino acid content averaged 45.13 mg/g DW. The average contents of 12 mineral elements were in the order of K > P > Ca > Mg > Mn > Fe > Zn > Cu > Ni > Se > Cr > Cd. K and P contents were the highest among all accessions, which were positively correlated with most of the other minerals. The average starch content of sweet potato was 53.90 g/100 g DW, ranging from 31.68 to 64.90%. The peak viscosity (PV), hot paste viscosity (HPV), and cold paste viscosity (CPV) were in the range of 90.7-318.8 Rapid Visco Unit (RVU), 77.3-208.3 RVU, and 102.6-272.7 RVU, respectively. The hardness values and cohesiveness (Coh) varied among different sweet potatoes, with a range of 8.20-18.48 g and 0.22-0.68, respectively. The gelatinization onset, peak, conclusion temperatures, and enthalpy were in the ranges of 59.39-71.91°C, 70.19-88.40°C, 78.98-95.79°C, 1.85-5.65 J/g, respectively.

Formulation and characterization of yogurt prepared with enzymatically hydrolyzed potato powder and whole milk powder

This study highlights the optimization of a suitable amount of enzymatically hydrolyzed potato powder (EHPP) with whole milk powder (WMP) to produce a quality yogurt. The yogurt was prepared with different levels of EHPP (0, 10, 15, 20, 25, 35 and 50% w/w) with WMP and evaluated after 24 h at 4 °C. The resulted product was analyzed on the basis of physicochemical, sensory, texture, antioxidant activity and microbiological analysis. The prepared yogurt showed a significant (p < 0.05) decrease in pH, protein and fat while acidity, moisture and ash contents were increased compared with control yogurt. In addition, textural parameters like hardness and adhesiveness were decreased while no significant (p < 0.05) change was found in springiness and cohesiveness. Moreover, color parameters such as L ^* and a ^* values decreased while b ^* values were increased. The current study suggested that the yogurt sample supplemented with 25% EHPP of WMP certainly improved the physicochemical, texture, microstructure, color, antioxidant and sensory properties of yogurt with EHPP. The prepared yogurt with EHPP provided an excellent flavor, satisfying sweetness, and homogeneous texture. The yogurt prepared from the EHPP presented potential industrial applications.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05112-6.

Proximate Composition, Physicochemical, Functional, and Antioxidant Properties of Flours from Selected Cassava (Manihot esculenta Crantz) Varieties

Cassava flour has a high potential to contribute as a raw material in the food industry. This study was aimed at characterizing flours from Sri Lankan cassava varieties with a view to explore the potential in food applications. Flours prepared from five cassava varieties, namely, Kirikawadi, MU51, Swarna, Shani, and Suranimala, were analyzed for proximate composition and physicochemical, functional, and antioxidant properties using standard methods. Flours from tested cassava varieties contained <1% crude fat and <2% crude protein. Flour from MU51 contained the highest amount of HCN (48.05 mg/kg) while flour from Suranimala contained the lowest (4.85 mg/kg). Total starch and amylose contents of flours were significantly lower (p < 0.05) than those of commercial wheat flour. Flour from Suranimala contained approximately similar amylopectin content as commercial wheat flour. Water absorption capacity, oil absorption capacity, water solubility index, swelling power, emulsion activity, and emulsion stability of flours from five cassava varieties were significantly higher (p < 0.05) than those of commercial wheat flour. Swarna was identified as the richest source of phenolic compounds (4.44 mmol GAE/100 g dry weight) among the five varieties. Results showed the promising application potential of flours from these five cassava varieties in different food applications such as weaning foods, bakery foods, and edible films.

Composition, morphology and physicochemical properties of starches derived from indigenous Ethiopian tuber crops: A review

Starch is a key food ingredient that can be extracted from roots, tubers, cereals, legumes and used in a variety of industrial applications. The issue of starch has received considerable critical attention. Most conventional sources of starch are being overexploited, it is necessary to investigate new botanical sources of starch to relieve pressure on traditional sources. Indigenous Ethiopian tuber crops can represent unexploited sources of starch with interesting characteristics in terms of potential uses as starch-based foods. It comes in a variety of shapes, sizes and properties allowing for a wide range of applications with high technological value in both the food and non-food industries. Compared to common starches, these starches have far fewer studies on their food and industrial applications. In the future, tubers grown Ethiopia could become another source of starch for the processor. This review summarizes current knowledge about the composition, structure, and physicochemical properties of Ethiopian tubers starches, intending to recommend future research to improve their use in the food industry. In the future, more in-depth work will be needed to reveal the mechanism of modification involved for structural change to use these starches for different purposes.