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The effects of fermentation with Lactobacillus plantarum on the volatile flavors of mung beans were studied using a gas chromatograph-ion mobility spectrometer, electronic nose, relative odor activity values and sensory evaluation. The main volatile compounds in unfermented mung beans were aldehydes such as nonanal, octanal and butanal, and esters such as ethyl hexanoate and ethyl acetate. The relative contents of the beany flavor components (1-octen-3-ol, hexanal and hexanol) were relatively high in the unfermented samples. The main volatile compounds of fermented mung beans (FMB) were acetic acid, ethyl hexanoate and ethyl acetate. The relative content of the beany flavor components in FMB decreased significantly, with hexanal changing the most. L. plantarum 23169 was most effective at removing the beany flavor. The electronic nose results showed that the flavor of L. plantarum 23169 FMB and L. plantarum 22699 FMB changed most and were similar, but the flavors from the three FMB samples could still be clearly distinguished. According to relative odor activity values, the special smell of FMB were fruity and grassy with no beany flavor, and sensory evaluation showed that L. plantarum YI-Y2013 provided a good "deodorization" effect, with the most obvious aromatic flavor and a high overall flavor coordination. • Mung bean volatile compounds included aldehydes, ketones, alkenes, alcohols, esters. • The beany flavor of mung bean was reduced by fermentation. • L. plantarum fermentation can improve the special smell of mung bean. • L. plantarum YI-Y2013 fermented mung bean had a higher overall flavor coordination. [ABSTRACT FROM AUTHOR]

Starch is the largest component in frequently consumed fresh rice noodles (FRN). The effects of morphology, relative crystallinity, molecular weight distribution and physicochemical (rheological, water hydration and gel texture) properties of starch from five rice cultivars with different amylose contents on the formation of FRN were investigated. FRN made from NR rice cultivar, used for commercial rice noodles making, showed excellent FRN texture. NR starch exhibited larger G′ and smaller tan δ values. The morphology of FRN from GM03 cultivar was closest to NR, but had higher hardness and lower springiness, resilience and cohesiveness. Its starch granules morphology was relatively small and round. The extracted starch from Zhongzao 35, Zao 87 and BX02 rice cultivars, with higher swelling power or lower proportions of amylose (FrI) and higher proportions of amylopectin (FrII), could not produce a dense and consistent FRN structure. It was observed that relative crystallinity of the starch samples had no influence on the formation of FRN. Nevertheless, the gel texture of starch played a role in the formation of FRN. The formation of FRN is the common effect of structure and physicochemical properties of rice starch. The finding of this research would be useful in understanding the role of starch in producing FRN of high quality. [Display omitted] • Both amylose and amylopectin affected the formation of the fresh rice noodles. • Larger storage modulus and smaller loss tangent led to more favorable noodle texture. • Higher swelling power of starch did not favor fresh rice noodles formation. • The texture of starch gels has a positive effect on the formation of noodle structure. [ABSTRACT FROM AUTHOR]

The physicochemical properties and starch fine structure change during paddy storage, which may be beneficial for the qualities of rice-based products such as fresh rice noodles (FRN). In this study, the textural properties of FRN prepared from polished rice of six indica paddy cultivars after different storage period at 36 ± 2 °C and 85% ± 5% relative humidity were investigated. The pasting properties, solubility (S), swelling power (SP) of rice flour and morphology of the starch granules, chain length distribution of amylopectin were analyzed to determine factors that impact the texture of FRN. The chewiness and springiness of FRN increased, and the adhesiveness decreased with increase in storage duration. The setback (SB) and pasting temperature (PT) increased while the S and SP decreased with extension of storage duration (0–90 days). Chain length distributions of amylopectin also changed. Pearson correlation analysis revealed that cool paste viscosity (CPV) of indica rice flour, short chain (DP 6–12) and long chain (DP 37–60) of amylopectin were the most correlated parameters with adhesiveness of FRN. Our results may provide insights for selecting raw materials for production of high-quality FRN. • Pasting properties, solubility and swelling power of rice changed with storage time. • Starch fine structure of different cultivars varied during storage. • Texture profiles of fresh rice noodles depend on storage time and rice varieties. • Cool peak viscosity of rice strongly corelated with adhesiveness of rice noodle. • Chain length of amylopectin strongly corelated with adhesiveness of rice noodle. [ABSTRACT FROM AUTHOR]

The study investigated the correlations between microbial compositions and volatile profiles of six mixed culture rice noodle fermentation liquid (RNFL) samples labelled by YI, XX, HL, XL, KJ, and JJ, respectively. Through 16S rRNA high-throughput sequencing technology (HTS), the main microbial genera identified in RNFL samples were Lactobacillus , Burkholderia , Gluconacetobacter , Lactococcus , and Leuconostoc (≥5% of operational taxonomic units). A total of one hundred and ten volatile compounds were detected by using SPME/GC-MS. E-nose data showed that HL, XX, and JJ shared similarities in flavor characteristics. Correlation analysis between bacterial genus and volatile compounds indicated that Lactobacillus and Gluconacetobacter were strongly correlated with most flavor compounds detected. Moreover, YI and XX had higher fragrance scores in sensory evaluation, indicating thicker fermented rice fragrance than other RNFL samples. • Microbial compositions of rice noodle fermentation liquid (RNFL) were analyzed. • Five bacterial species were identified as the main microbial genera in RNFL. • Correlation between microbial compositions and volatile profiles were investigated. • Lactobacillus and Gluconacetobacter were strongly associated with aroma profiles. [ABSTRACT FROM AUTHOR]

Abstract: Microstructure and rheological properties of mixtures of acid-deamidated rice protein (ADRP) and dextran were studied. The microstructures of the ADRP/dextran mixtures were described using confocal laser scanning microscopy (CLSM), which revealed the effective association among ADRP and formation of a protein network-like structure in the mixture with higher protein concentration. Mechanical properties of the mixtures were observed by rheometer. The steady shear measurements showed a correlation with the CLSM results via a marked increase in the viscosity of the mixtures with protein association. Frequency sweeps further evidenced the build-up of the gelled network-like structure. The differences in fracture forces observed by textural measurements between mixture and single ADRP gel also suggested the difference in microstructures. The formation of network-like structure appeared to have occurred through a phase separation of ADRP and dextran. [Copyright &y& Elsevier]

Fermentation technology is a useful tool to modifying starch, and the relationship between starch structure and digestibility is a crucial parameter that affects fermentation technology. In this study, the changes in digestibility and starch structure of indica rice during fermentation by Lactobacillus plantarum were investigated. The relationship between digestibility and the changes in starch composition, amylose content, chain length distribution of amylopectin, short-range ordered structure, and relative crystallinity was analyzed. The results showed that during the fermentation of indica rice by L. plantarum , the glycemic index (GI) of the indica rice decreased, and after 60 h of fermentation, the GI of indica rice decreased from 82.88 to 74.53. Additionally, the contents of slowly digestible starch (SDS) and resistant starch (RS) increased. Furthermore, the proportion of short chain of amylopectin increased, which facilitated the intermolecular interaction of short chain to form a compact and orderly structure. This led to an increase in short-range ordered structure and relative crystallinity of indica rice starch. These structural changes promoted the stability of starch structure, resulting in a decrease in rice digestibility. This work has significant implications for the development of low-GI rice and rice-based foods. • The GI of L.plantarum fermentated rice decreased with the extension of fermentation time. • The multi-scale structure of starch enhanced after L. plantarum fermentation. • The relationship between the digestibility of fermented rice and structure of starch has been discussed. [ABSTRACT FROM AUTHOR]

To investigate the effects of hot air treatment (HAT) on the quality attributes of Indica rice semidry-milling, HAT was applied at various temperatures (45–120 °C) and processing times (0–240 min). The changes in grain-surface cracking, moisture absorption rate, damaged starch, rheological properties, microbial decontamination, and texture qualities were evaluated. HAT induced many cracks in the rice grains, shortening the soaking time to reach maximum water content (28%) to 8 min. However, at high temperatures, extending the HAT time slowed the water absorption rate. Under the optimum HAT conditions and soaking time, the total viable counts in the rice flour were similar to those of dry-milled rice flour (10 2 –10 3 cfu/g), with no coliforms and few yeasts and molds. The damaged starch content, rheological and texture properties were similar to those of wet-milling. Therefore, an appropriate HAT can shorten the soaking time of the rice and clean it during the milling process. [ABSTRACT FROM AUTHOR]

This study isolated four strains of Bacillus from slimy fresh rice noodles (FRN) and preliminary identified them as B. cereus , B. amyloliquefaciens , B. altitudinis , and B. subtilis , respectively, using morphological, physiological, and genetic analyses. The spoilage potential of each of these strains was then evaluated in FRN. The results indicated that both B. amyloliquefaciens and B. subtilis can cause FRN to become sticky and smelly, accompanied by an increase of acidity and high amylase activity. B. cereus and B. altitudinis mainly caused odor deterioration of FRN. There were 29, 20, 25, 25, and 27 volatile organic compounds (VOCs) identified from control FRN and FRN samples inoculated with B. cereus , B. amyloliquefaciens , B. altitudinis , and B. subtilis , respectively. The compositions of VOCs in the samples inoculated with B. amyloliquefaciens and B. subtilis were similar; esters, volatile organic acids, and acetoin were the main volatile compounds in the FRN. For B. cereus and B. altitudinis , the main adverse flavor substances were acetic acid and ammonia. This study provides a theoretical basis for quality control in the production, storage, and sale of FRN. • Four Bacillus strains isolated and identified from slimy fresh rice noodles (FRN). • Four strains were preliminary identified as B. cereus , B. amyloliquefaciens , B. altitudinis , and B. subtilis. • B. amyloliquefaciens and B. subtilis can cause FRN to become sticky and smelly. • B. cereus and B. altitudinis mainly caused odor deterioration of FRN. [ABSTRACT FROM AUTHOR]