Effect of lactobacteria fermentation on structure and physicochemical properties of Chinese yam starch (Dioscorea opposita Thunb.)

Effects of fermentation with Lactobacillus plantarum on rice flour: The role of granular characteristics

This study examined the effects of lactic acid bacteria fermentation on the physicochemical and functional properties of the flours from two rice varieties, Shindongjin (SF) and Hitomebore (HF), both with similar amylose content. Fermentation with Lactobacillus plantarum over 48 h resulted in significant changes. Protein content decreased substantially in both varieties, especially in SF, and amylose content increased. Swelling power and solubility also increased more in SF. The gel hardness of fermented SF increased by approximately 22 %, whereas HF showed minimal change. These differences are due to variations in granule rigidity and starch molecule leaching. SF granules maintained rigidity and a robust external network due to higher amylose leaching. In contrast, the lower initial rigidity and higher amylopectin leaching in HF hindered strong gel network formation. These findings offer insights into the structural and molecular mechanisms of rice fermentation with lactic acid bacteria.

Physicochemical evolution of sorghum grain starch under the condition of solid-state fermentation of Baijiu

Glutinous sorghum grains were fermented for varying durations (1, 2, 3, 5, 8 and 12 w) to investigate the effects of fermentation on the starch within the grains. Starch conversion rate and Baijiu yield continued to increase in the first 8 w of fermentation, peaking at 63.7 % and 45.7 %, respectively. The increasing rate was about eight times the subsequent decline rate. Images of CLSM revealed that the swollen starch granules progressively vanished during fermentation, transforming into irregular fragments. The total starch content decreased by 69.0 %, and almost only amylopectin remained in the grains at 12 w. The utilization rate of amylose (98.3 %) was higher than that of amylopectin (66.2 %), and the higher the amylose content, the faster the production of Baijiu. Additionally, fermentation reduced high-molecular-weight components and increased low-molecular-weight ones. The weight average molecular weight (Mw) of starch in the grains dropped from 9.13×107 g/mol to 8.02×105 g/mol. The considerable decline in starch content and molecular weight led to a substantial decrease in the final viscosity of sorghum flour, from 392 cP to below 10 cP. The findings provide a theoretical basis for intelligent control of multi-round fermentation in the Baijiu brewing industry.

Structural and functional properties of polysaccharides extracted from three Dioscorea species

Dioscorea has a history spanning over 2000 years for both medicinal and edible purposes in China. It contains rich polysaccharides, which are frequently utilized as thickening and stabilizing agents in the food industry. However, there has been relatively little focus on polysaccharides from common Dioscorea species besides D. opposita, such as D. alata and D. esculenta. In this study, non-starch crude polysaccharides were isolated from D. opposita (BD), D. alata (WC), and D. esculenta (GZ). Their structures, physicochemical compositions, and functional properties were characterized and compared. The results indicated three polysaccharides all exhibited characteristic peaks of polysaccharides and possessed triple-helix structures. The Glc (36.78-83.90 %), Man (6.71-26.68 %), and GalA (8.54-10.22 %) were identified as the primary monosaccharide components. In terms of functionality, three polysaccharide solutions demonstrated non-Newtonian flow characteristics and displayed commendable thermal stability. It is worth noting that the antioxidant and emulsifying properties of polysaccharides isolated from D. opposita (BD) and D. alata (WC) were superior to those of D. esculenta (GZ), making them more suitable for use as antioxidants and stabilizers. By comparing polysaccharides derived from different Dioscorea species, this study provides valuable insights into the food, cosmetic, and pharmaceutical industries based on the unique properties of these different polysaccharides.

The Physicochemical Properties and Structure of Mung Bean Starch Fermented by Lactobacillus plantarum

Understanding the relationship between gel formation and the hierarchical structure of mung bean starch fermented by Lactobacillus plantarum has potential value for its green modification and quality improvement. The variations in characteristics, including gelation characteristics, starch chain, and the molecular order degree of mung bean starch fermented by different L. plantarum, were compared. The results show that in the gelation process, starch began to disintegrate at 65 °C, indicating a critical temperature for structural changes. Compared with the control group, although the effects of different L. plantarum sources on mung bean starch varied, notable improvements were observed in water absorption across all groups of fermented starch, along with reduced free water-soluble substances and enhanced anti-expansion ability. This led to the easier formation of gels with higher viscosity, primarily attributed to decreased crystallinity, increased short-chain amylopectin tendency, an elevated amylose content, and enhanced short-range order when microorganisms acted on the crystallization zone. In conclusion, although L. plantarum came from different sources, its action mode on mung bean starch was similar, which could enhance the gel structure.

The structural properties of "Huilou" yam starch fermented with five microbial species

In this study, we employed two lactic acid bacterial species, two yeast species, and Bacillus amyloliquefaciens to ferment "Huilou" yam starch. The aim was to explore the effects of fermentation time and microbial species on the structural properties of yam starch. The results showed that fermentation caused an increase in relative crystallinity (29.23 %-37.98 %) compared with native starch (25.69 %). The fermentation process altered the thermal properties of yam starch, leading to higher enthalpy of gelatinization values compared with unfermented starch. Notably, an absorption peak of native starch shifted from 992 cm-1 to 1015 cm-1 upon 2-day fermentation by Bacillus amyloliquefaciens and 5-day fermentation by Lactobacillus plantarum or Pediococcus pentococcus, associated with an increase in the presence of amorphous structures in yam starch. "Huilou" yam starch obtained through lactic acid bacterial fermentation exhibited a significant presence of organic acids, whereas samples derived from Bacillus amyloliquefaciens fermentation were primarily affected by amylase activity. Following yeast fermentation, organic acids and amylase were observed, albeit with relatively low influence. This research reveals that microbial fermentation can potentially alter the structural characteristics of yam starch, which can improve the quality of yam starch-based foods.

Effects of Lactobacillus plantarum fermentation on the structure, physicochemical properties, and digestibility of foxtail millet starches

This study investigated the effects of Lactobacillus plantarum fermentation on the structural, physicochemical, and digestive properties of foxtail millet starches. The fermented starch granules formed a structure with honeycomb-like dents, uneven pores, and reduced particle size. As the fermentation time extended, the amylose content of waxy (0.88 %) and non-waxy (33.71 %) foxtail millet starches decreased to the minimum value at 24 h (0.59 % and 29.19 %, respectively), and then increased to 0.85 % and 31.87 % at 72 h, respectively. Both native and fermented foxtail millet starches exhibited an A-type crystal structure. Compared with native samples, the fermented samples performed enhanced proportion of short-branched chain, crystallinity, and short-range ordered degree. After fermentation for 24 h, the solubility, adsorption capacity, and pasting viscosity of foxtail millet starches improved, whereas the swelling power, pasting temperature, breakdown, setback, and degree of retrogradation reduced. Additionally, fermentation increased the transition temperatures, enthalpy, and digestibility. Overall, Lactobacillus plantarum fermentation is considered a competent choice to regulate the characteristics of foxtail millet starch.

Effect of radio frequency explosion puffing on physicochemical, functional and crystalline properties, and in vitro digestibility of yam flour

Yam flour was modified by radio frequency explosion puffing at different moisture content, puffing temperature, and puffing pressure difference. After puffing, the protein content and lipid content increased by 0.56-1.28 % and 0.23-0.39 %, respectively. Puffing caused the flour granules to aggregate, increasing the thermal transition temperatures and reducing the pasting viscosities, enthalpy, 1047/1022 cm-1 ratio, and relative crystallinity. Puffing reduced the intensity of the infrared spectrum peak at 1641 cm-1 by breaking the hydrogen bonds without changing A-type crystalline structure. Puffing promoted the conversion of random-coil and α-helix protein structure to β-turn and β-sheet. Puffing retarded in vitro digestibility by reducing rapidly digestible starch content by 7.04-11.12 % and rising slowly digestible starch content and resistant starch content by 4.02-4.89 % and 2.77-3.10 %, respectively. Radio frequency explosion puffing altered flour's physicochemical, functional and digestibility properties by destroying the protein structure and promoting the interaction of starch and proteins/lipids.

A review of the effects of fermentation on the structure, properties, and application of cereal starch in foods

Fermentation is one of the oldest food processing techniques known to humans and cereal fermentation is still widely used to create many types of foods and beverages. Starch is a major component of cereals and the changes in its structure and function during fermentation are of great importance for scientific research and industrial applications. This review summarizes the preparation of fermented cereals and the effects of fermentation on the structure, properties, and application of cereal starch in foods. The most important factors influencing cereal fermentation are pretreatment, starter culture, and fermentation conditions. Fermentation preferentially hydrolyzes the amorphous regions of starch and fermented starches have a coarser appearance and a smaller molecular weight. In addition, fermentation increases the starch gelatinization temperature and enthalpy and reduces the setback viscosity. This means that fermentation leads to a more stable and retrogradation-resistant structure, which could expand its application in products prone to staling during storage. Furthermore, fermented cereals have potential health benefits. This review may have important implications for the modulation of the quality and nutritional value of starch-based foods through fermentation.

Research progress on the structure, derivatives, pharmacological activity, and drug carrier capacity of Chinese yam polysaccharides: A review

Chinese yam is a traditional Chinese medicine that has a long history of medicinal and edible usage in China and is widely utilised in food, medicine, animal husbandry, and other industries. Chinese yam polysaccharides (CYPs) are among the main active components of Chinese yam. In recent decades, CYPs have received considerable attention because of their remarkable biological activities, such as immunomodulatory, antitumour, hypoglycaemic, hypolipidaemic, antioxidative, anti-inflammatory, and bacteriostatic effects. The structure and chemical alterations of polysaccharides are the main factors affecting their biological activities. CYPs are potential drug carriers owing to their excellent biodegradability and biocompatibility. There is a considerable amount of research on CYPs; however, a systematic summary is lacking. This review summarises the structural characteristics, derivative synthesis, biological activities, and their usage as drug carriers, providing a basis for future research, development, and application of CYPs.

Effects of Lactiplantibacillus plantarum dy-1 fermentation on multi-scale structure and physicochemical properties of barley starch

The effects of fermentation on barley starch were studied using Lactiplantibacillus plantarum dy-1. Changes in multi-scale structure and physicochemical properties of barley starch were studied. The chain structure results revealed that fermentation could increase the content of short chain and medium short chain by breaking down long amylopectin side chains in barley and increase amylose content by debranching amylopectin. Also, fermentation promoted the arrangement of short chains into short order structure, leading to the enhancement of hydrogen bond interaction. Furthermore, it improved the helical structure content and relative crystallinity of barley starch by degrading the amorphous structure of barley starch. In terms of physicochemical properties, fermentation inhibited the hydration characteristics of barley starch, thus improving its thermal stability. It also enhanced shear stability, resistance to short-term aging and digestion, and improved gel texture properties. These findings offer potential for the processing and nutritional regulation of fermented barley products.

Multiscale structure-property relationships of oxidized wheat starch prepared assisted with electron beam irradiation

In this study, two promising eco-friendly modification techniques, electron beam (EB) irradiation and hydrogen peroxide (H₂O₂) oxidation, were used to prepare oxidized wheat starch. Neither irradiation nor oxidation changed starch granule morphology, crystalline pattern, and Fourier transform infrared spectra pattern. Nevertheless, EB irradiation decreased the crystallinity and the absorbance ratios of 1047/1022 cm^-1 (R_1047/1022), but oxidized starch exhibited the opposite results. Both irradiation and oxidation treatments reduced the amylopectin molecular weight (Mw), pasting viscosities, and gelatinization temperatures, while increasing the amylose Mw, solubility and paste clarity. Notably, EB irradiation pretreatment dramatically elevated the carboxyl content of oxidized starch. In addition, irradiated-oxidized starches displayed higher solubility, paste clarity, and lower pasting viscosities than single oxidized starches. The main reason was that EB irradiation preferentially attacks the starch granules, degrades the starch molecules, and depolymerizes the starch chains. Therefore, this green method of irradiation-assisted oxidation of starch is promising and may promote the appropriate application of modified wheat starch.

Effect of Fermentation on the Quality of Dried Hollow Noodles and the Related Starch Properties

Crumbly dough fermentation was applied to produce dried hollow noodles, with Lactobacillus plantarum, Koji and yeast as the main fermenting agents. The cooking, textural and digestive properties of the noodles were studied, followed by the morphological, crystalline and thermal properties of the starch. The results show that, compared to unfermented noodles, the optimal cooking time of Koji pre-fermented noodles (KJHN) decreased from 460 s to 253 s, and they possessed a higher percentage of weakly bound water and degree of gelatinization at the same cooking time. After cooking, KJHN had a softer texture and higher starch digestibility. In addition, the physicochemical properties of the KJHN and Lactobacillus plantarum pre-fermented noodles (LPHN) showed a decrease in pH and amylose content, and an increase in reducing sugars content. The starch extracted from KJHN and LPHN had significant superficial erosion and pore characteristics, and the gelatinization enthalpy, relative crystallinity and short-range order were all increased. These changes in the starch properties and the quality characteristics of noodles resulting from Koji fermentation might provide a reference for the development of easy-to-cook and easy-to-digest noodles.

Effects of Extraction Methods on Physicochemical and Structural Properties of Common Vetch Starch

Three extraction methods: water extraction, lactic acid bacteria fermentation, and back-slopping fermentation were applied to extract a new type of legume starch, common vetch starch. Our results showed that the lactic acid bacteria fermented starch had the highest amylose content (35.69%), followed by the back-slopping fermented starch (32.34%), and the water-extracted starch (30.25%). Furthermore, erosion surface, lower molecular weight, smaller particle size, larger specific surface area, and a higher proportion of B1 chain were observed in the fermented starch, especially in the back-slopping fermented starch. All the extracted starches showed a type C structure, but a type C_B structure was observed in the back-slopping fermented starch. In addition, the relative crystallinity of the lactic acid bacteria fermented starch (34.16%) and the back-slopping fermented starch (39.43%) was significantly higher than that of the water-extracted starch (30.22%). Moreover, the swelling power, solubility, pasting, and thermal properties of the fermented starches were also improved. In conclusion, the fermentation extraction method, especially back-slopping fermentation, could improve the quality of the extracted common vetch starch when compared with the traditional water extraction method.