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- Author or Editor: Sz. Gergely x
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Abstract
Soybean seeds were germinated on an industrial scale after soaking for 0–56 h to produce a special additive for food industrial use. The germination process of three soybean varieties was monitored with near-infrared (NIR) spectroscopy based on changes in the amount, status, or character of the water. This paper evaluates the “waterless” NIR spectra of sound, germinated, and heat treated seeds to try to follow the fine details of the germination process. The germination process was analysed with the help of cluster analysis (CA), principal component analysis (PCA), and polar qualification system (PQS) as statistical and chemometric methods. PCA proved to be the most sensitive spectrum evaluation method to follow the fine details of germination. The applied NIR method is suitable for non-destructively, real-time monitoring of the non-linear nature of germination.
Resistant starches (RS) can be used in the food industry aiming to enhance the dietary fibre content and reduce the glycaemic response of food. The aim of the present study was to investigate the physical and chemical properties of different resistant starches (origin, type of resistance) and their comparison with native starches in pure form and in stoichiometric mixtures. Measurements were carried out to determine enzymatic digestibility, water absorption, thermogravimetric parameters (DSC), and viscometric characteristics (RVA) of resistant and native starches and their mixtures. Enzymatic digestibility and water absorption were reduced linearly by adding resistant starches into the mixtures. RVA parameters have shown non-proportional character in the stoichiometric mixtures. The results of DSC measurements proved that the gelatinisation of resistant starches is quite different and only chemically modified resistant starch was heat-sensitive. Results indicated that circumspect evaluation is needed in the selection of resistant starch products for the development and innovation of food products with reduced glycaemic response.
The proteins that form gluten of a winter wheat cultivar, Ukrainka (HMW-GS composition 1, 7+8, 5+10) grown in Hungary and harvested in the year 2006, was investigated during grain development. The formation of gluten, its protein fractions and composition of polymeric fraction, were followed starting at the 12 th day after anthesis (DAA) to the 52 nd .Gluten formation was first observed (manual method of determination) only 20–25 days after anthesis and its quantity increased rapidly during the next period of grain development. The gluten was separated to a fraction extractable with SDS-phosphate buffer and another fraction, unextractable by this buffer. An increase in the ratio of unextractable polymeric protein (UPP)/soluble protein fraction was observed during grain development. As expected, gliadin was the main component of the soluble fraction and glutenin that of the insoluble one. HMW monomers were detected in unreduced fractions in small quantities only until 30 th DAA. RP-HPLC of reduced gluten fractions showed a slight increase of the ratio HMW/LMW with days after anthesis.An increase of relative viscosity of gluten solutions during grain development was also observed as a sign of polymerization of glutenin subunits and consequently an increase in average molecular weight of glutenin.
