Preparation and Characterization of Extruded Yam Starch-Soy Protein Isolate Complexes and Their Effects on the Quality of Dough

Resistant starch from yam: Preparation, nutrition, properties and applications in the food sector

Yam is a significant staple food and starch source, particularly in tropical and subtropical regions, holding the fourth position among the world's top ten tuber crops. Yam tubers are rich in essential nutrients and a diverse range of beneficial plant compounds, which contribute to their multifaceted beneficial functions. Furthermore, the abundant starch and resistant starch (RS) content in yam can fulfil the market demand for RS. The inherent and modified properties of yam starch and RS make them versatile ingredients for a wide range of food products, with the potential to become one of the most cost-effective raw materials in the food industry. In recent years, research on yam RS has experienced progressive expansion. This article provides a comprehensive summary of the latest research findings on yam starch and its RS, elucidating the feasibility of commercial RS production and the technology's impact on the physical and chemical properties of starch. Yam has emerged as a promising reservoir of tuber starch for sustainable RS production, with thermal, chemical, enzymatic and combination treatments proving to be effective manufacturing procedures for RS. The adaptability of yam RS allows for a wide range of food applications.

Influence of key component interactions in flour on the quality of fried flour products

In the field of food, the interaction between various components in food is commonly used to regulate food quality. Starches, proteins, and lipids are ubiquitous in the food system and play a critical role in the food system. The interaction between proteins, starches, and lipids components in flour is the molecular basis for the formation of the classical texture of dough, and has a profound impact on the processing properties of dough and the quality of flour products. In this article, the composition of the key components of flour (starch, protein and lipid) and their functions in dough processing were reviewed, and the interaction mechanism of the three components in the dynamic processing of dough from mixing to rising to frying was emphatically discussed, and the effects of the components on the network structure of dough and then on the quality of fried flour products were introduced. The analysis of the relationship between dough component interaction, network structure and quality of fried flour products is helpful to reveal the common mechanism of quality change of fried flour products, and provide a reference for exploring the interaction of ingredients in starch food processing.

Effect of extrusion on the formation, structure and properties of yam starch-gallic acid complexes

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch.

Effect of Konjac Glucomannan on Structure, Physicochemical Properties, and In Vitro Digestibility of Yam Starch during Extrusion

In this study, the effect of konjac glucomannan (KGM, 0-5%) on the structure, physicochemical properties, and in vitro digestibility of extruded yam starch (EYS) was investigated. The EYS became rougher on the surface and the particle size increased as observed using scanning electron microscopy and particle size analysis. X-ray diffraction and Raman results revealed that the relative crystallinity (18.30% to 22.30%) of EYS increased, and the full width at half maxima at 480 cm-1 decreased with increasing KGM content, indicating the increment of long-range and short-range ordered structure. Differential scanning calorimetry and rheological results demonstrated that KGM enhanced thermal stability and the gel strength of EYS due to enhanced interaction between KGM and YS molecules. Additionally, a decrease in the swelling power and viscosity of EYS was observed with increased KGM content. The inclusion of KGM in the EYS increased the resistant starch content from 11.89% to 43.51%. This study provides a dual-modified method using extrusion and KGM for modified YS with high thermal stability, gel strength, and resistance to digestion.

Mechanism of feed moisture levels in extrusion treatment to improve the instant properties of Chinese yam (Dioscorea opposita Thunb.) flour

Extruded yam flour was prepared at different feed moisture to improve its instant properties. The water solubility index (WSI) and water absorption index (WAI) were used to compare the instant properties of yam flour. Their chemical compositions, particle size distribution, crystalline structure, and microscopic forms were also analyzed to assess the effects of feed moisture on the instant properties of yam flour. We found that extrusion significantly improved the instant properties of yam flour, while the WSI value increased from 29.50% to 71.86% and the WAI value decreased from 387.88% to 228.06% with decreased feed moisture. Extrusion led to the degradation of total starch and amylopectin, and the contents of soluble substances increased markedly. Extrusion destroyed the granular and crystalline structures, which were reconstituted as amylose-lipid complexes with a significant decrease in relative crystallinity. Increasing the feed moisture was beneficial to the flow and color retention, while lower feed moisture was more favorable to enhance the instant properties.

Physical modification of vegetable protein by extrusion and regulation mechanism of polysaccharide on the unique functional properties of extruded vegetable protein: a review

Development and utilization of high quality vegetable protein resources has become a hotspot. Food extrusion as a key technology can efficiently utilize vegetable protein. By changing the extrusion conditions, vegetable protein can obtain unique functional properties, which can meet the different needs of food processing. However, extrusion of single vegetable protein also exposes many disadvantages, such as low degree functional properties, poor quality stability and lower tissue fibrosis. Therefore, addition of polysaccharide has become a new development trend to compensate for the shortcomings of extruded vegetable protein. The unique functional properties of vegetable protein-polysaccharide conjugates (Maillard reaction products) can be achieved after extrusion due to regulation of polysaccharides and adjustment of extrusion parameters. However, the physicochemical changes caused by the intermolecular interactions between protein and polysaccharide during extrusion are complex, so control of these changes is still challenging, and further studies are needed. This review summarizes extrusion modification of vegetable proteins or polysaccharides. Next, the effect of different types of polysaccharides on vegetable proteins and its regulation mechanism during extrusion is mainly introduced, including the extrusion of starch polysaccharide-vegetable protein, and non-starch polysaccharide-vegetable protein. Finally, it also outlines the development perspectives of extruded vegetable protein-polysaccharide.