Study of the protein, antioxidant activity, and starch during in vitro simulated digestion of green wheat and wheat cooked flours

Comprehensive Assessment of Polysaccharides Extracted from Squash by Subcritical Water under Different Conditions

The effects of subcritical water microenvironment on the physiochemical properties, antioxidant activity and in vitro digestion of polysaccharides (SWESPs) from squash were investigated. After single-factor experiments, twenty samples were successfully prepared at different extraction temperatures (110, 130, 150, 170 and 190 °C) and extraction times (4, 8, 12 and 16 min). Under a low temperature environment, the whole process was mainly based on the extraction of SWESP. At this time, the color of SWESP was white or light gray and the molecular mass was high. When the temperature was 150 °C, since the extraction and degradation of SWESP reached equilibrium, the maximum extraction rate (18.67%) was reached at 150 °C (12 min). Compared with traditional methods, the yield of squash SWESP extracted by subcritical water was 3-4 times higher and less time consuming. Under high temperature conditions, SWESPs were degraded and their antioxidant capacity and viscosity were reduced. Meanwhile, Maillard and caramelization reactions turned the SWESPs yellow-brown and produced harmful substances. In addition, different SWESPs had different effects on in vitro digestion. In brief, SWESPs prepared under different conditions have different structures and physicochemical properties, allowing the obtainment of the required polysaccharide. Our results show that squash polysaccharides prepared in different subcritical water states had good development potential and application in the food industry.

Effects of zucchini polysaccharide on pasting, rheology, structural properties and in vitro digestibility of potato starch

Zucchini polysaccharide (ZP) has a unique molecular structure and a variety of biological activities. This study aimed to evaluate the effects of ZP (1, 2, 3, 4 and 5 %, w/w) on the properties of potato starch (PS), including pasting, rheological, thermodynamic, freeze-thaw stability, micro-structure, and in vitro digestibility of the ZP-PS binary system. The results showed that the appearance of ZP significantly reduced the peak, breakdown, final and setback viscosity and prolonged the pasting temperature of PS, whereas increased the trough viscosity. The tests of rheological showed that ZP had a damaging effect on PS gels. Meanwhile, the results of thermodynamic and Fourier transform infrared exhibited that the presence of ZP significantly retarded the retrogradation of PS, especially at a higher levels. The observation of the microstructure exhibited that ZP significantly altered the microscopic network structure of the PS gels, and ZP reduced the formation of the gel structure. Besides, ZP postponed the retrogradation process of PS gels. Moreover, ZP weakened the freeze-thaw stability of the PS gel. Furthermore, ZP also can decrease the digestibility and estimated glycemic index (eGI) value of PS from 86.04 % and 70.89 to 77.67 % and 65.22, respectively. Simultaneously, the addition of ZP reduced the rapidly digestible starch content (from 25.09 % to 16.59 %) and increased the slowly digestible starch (from 24.99 % to 26.77 %) and resistant starch content (from 49.92 % to 56.64 %). These results have certain guiding significance for the application of ZP in starch functional food.

The Role of Ancient Grains in Alleviating Hunger and Malnutrition

Meeting the United Nation's sustainable development goals for zero hunger becomes increasingly challenging with respect to climate change and political and economic challenges. An effective strategy to alleviate hunger and its severe implications is to produce affordable, nutrient-dense, and sustainable food products. Ancient grains were long-forgotten due to the dominance of modern grains, but recently, they have been rediscovered as highly nutritious, healthy and resilient grains for solving the nutrition demand and food supply chain problems. This review article aims to critically examine the progress in this emerging field and discusses the potential roles of ancient grains in the fight against hunger. We provide a comparative analysis of different ancient grains with their modern varieties in terms of their physicochemical properties, nutritional profiles, health benefits and sustainability. A future perspective is then introduced to highlight the existing challenges of using ancient grains to help eradicate world hunger. This review is expected to guide decision-makers across different disciplines, such as food, nutrition and agronomy, and policymakers in taking sustainable actions against malnutrition and hunger.

Study on the in vitro digestion process of green wheat protein: Structure characterization and product analysis

In this study, the in vitro digestion process of green wheat protein (GWP) was explored by simulating the gastrointestinal digestion. The digestibility of GWP was 65.23%, and was mainly digested by trypsin. During the digestion process of GWP, large-size particles are digested by pepsin, and medium-sized particles are digested by trypsin into smaller particles; irregular large block structure with smooth surface was gradually turned into smaller blocks with porous surface; and the spatial conformation was loosened mainly by the unfolding of β-sheet structure. Gel electrophoresis demonstrated that HMW glutenin and ω-gliadins in GWP were completely digested, while LMW glutenin and α/β/γ-gliadins were partially digested. Additionally, the peptide lengths were relatively dispersed after pepsin digestion. Most of the peptides (76.5%) fell into the range 3-15 amino acid after pepsin and trypsin digestion. The molecular weight (MW) of most pepsin digestion products was above 2000 Da, whereas the MW of trypsin digestion products was mainly concentrated in 500-2000 Da. Besides, the sensitizing peptide sequence of wheat protein was detected in the final digestion products of GWP. This research provided a theoretical guidance for the development and application of GWP.

Analysis of volatile flavor compounds of green wheat under different treatments by GC-MS and GC-IMS

Volatile components in green wheat under different treatments including raw, washing, blanching, precooling, freezing, steaming, boiling, frying, and freeze-drying were evaluated by gas chromatography-ion mobility spectroscopy (GC-IMS) and gas chromatography-mass spectrometry (GC-MS). Five key aroma substances including n-hexanal, benzaldehyde, nonanal, 2-pentylfuran, and (E)-oct-2-enal were found by Venn diagram and odor activity values (OAV). Furthermore, according to volatile fingerprints characteristics and the aroma profile of sensory evaluation, it was found that green wheat under different treatments mainly presented seven characteristic flavor notes including sweet flowers, fat fragrance, mushroom hay, waxy aldehyde, citrus fruity, vegetable-like bean, and bitter almond from the sensory evaluation, and they could be divided into four categories, which was consistent with the results of PCA and GC-IMS. Hence, the volatile compounds of green wheat samples could be visualized and identified quickly via GC-IMS and the samples could be clearly classified based on the difference of volatile compounds. PRACTICAL APPLICATIONS: In the study, fingerprints coupled with cluster analysis were a visualized method for the identification of volatile compounds. Meanwhile, a new method, Venn diagram with OAV, was used to identify the key aroma of products. Finally, a rapid method to classify products by GC-IMS was performed. In future practical applications, GC-IMS can be used to classify products from different origins and different manufacturers. Similarly, it can identify fake and inferior products and whether the products have deteriorated. In addition, this research will provide a new strategy to find the relationship between flavor compounds and various processed technologies toward different cereals.