| China accounts for 35% of global rice production and 2/5 of total domestic grain production. About 55% of rice yield is consumed directly as cooked rice. Only 6% is used for processing in China. Consequently, there is as much as 33% of total rice yield overstocked in farmers or storehouses, and about 80% of the overstocked rice is Indica, which causes large quantity of deterioration every year. Rice cultivars Indica is widely planted with its high yield and good quality for producing rice noodles in South of China. Identification of new uses for Indica rice is necessary to generate great demand for it.Traditional fermented rice noodles are very popular because of its favorite mouth-feel and taste in China. The further theoretical research is needed for its industrialized production. In this study, the processing technology of fermented rice noodles was thoroughly investigated; the evolution of microbial population were tracked in time course; the varieties of fermentation microorganisms were counted, isolated, and screened; fermentation effect and modification mechanism on starch granule structure and molecular structure were determined, simulated, and validated. The main contents and results are as follows.1. Chemical components of rice flour were significantly modified by whole rice granule fermentation. About 33% of total protein, 61% of total lipid and 62% of total ash content were lost during fermentation period. The purity of rice starch was improved. A large quantity of organic acid was produced from low weight molecular sugars. More than 90% of total acid is lactic acid by Ion Chromatography analysis. The rice starch content remained almost constant, but the starch structure and constituents were changed by fermentation. The amylose content had a 3.28% increase.2. Starch modification was analyzed by using GPC (Gel Permeation Chromatography, equipped with two consecutive columns: Sepharose CL-2B and Sephadex G-50 respectively). Starch molecular profile could be divided into two distinct fractions (Fr I and Fr II). Fr I is the larger molecular and FrII is the smaller one. The area of FrII fraction increased but Fr I fraction decreased because the larger molecular starch was degraded by fermentation. The number of average molecular polymerization was changed from 12597.6 GLU to 12051.0 GLU for Fr I and from 3061.5 GLU to 3423.1 GLU for FrII after fermentation. The (3-hydrolysis ratio was increased. It showed that starch chain was broken and debranched. Amylopectin fraction (Fr I ) could further be fractionated into two distinct fractions after debranched by isoamylase and pullulanase treatment. The average chain length of first fraction decreased from 55.6 GLU to 52.9 GLU and second fraction increased by 2.7 GLU after fermentation. These results indicated that the chain breaking occurred mainly on the long chains of the amylopectin molecules.3. Effects of fermentation on starch granule structure and thermal properties were determined by using X-ray diffraction, FTIR, DSC and RVA. Results indicated that fermentation had little effect on starch crystal structure, but the ratio of crystal area to amorphous area increased; the gelatinization temperature (Tp) of rice starch decreased, starch gelatinization time prolonged, and the gelatinization enthalpy (AH) increased; RVA peak viscosity decreased. Results proved that fermentation mainly affected the amorphous region of the starch granule structure. The micrography of starch granule showed that the shape of starch granule remained unchanged. It also indicated that starch modification by fermentation took place inside the granule.4. The varieties and populations of the natural fermentation microorganisms were inspected throughout the fermentation period. The main source of microorganisms was from rice itself with initial bacterial count up to 105cfu/mL, mainly consisting of lacto bacilli and yeasts. Results showed that the fermentation of whole rice granules took place under an anaerobic condition. Lacto bacilli were the domi...
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