Modification of wheat gluten for improvement of binding capacity with keratin in hair

In this study, enzymatic hydrolysis and cationization with epoxypropyldodecyldimethylammonium chloride of wheat protein, an economic protein complex containing great amount of disulfide bonds, were conducted to improve properties such as solubility and disassociation behaviour for recovery of damaged hair when used in shampoo. The optimal conditions for enzymatic hydrolysis were pH 8.2, 55°C with Alcalase for 60 min. After the selected hydrolysis, the degree of hydrolysis, nitrogen solubility index, foaming capacity index, foam stability index, emulsifying activity index and emulsion stability index of hydrolysate with 58.71% of short-chain peptides (less than 1000 Da) were 8.81%, 39.07%, 225%, 56.67%, 9.62 m 2 g −1 and 49.08, respectively. The cationization was followed to raise the isoelectric point of wheat protein hydrolysate from 7.0 to 10.0, which could facilitate the quaternized protein hydrolysate to adhere to the surface of hair at the range of pH 5–6 of hair care products to form more disulfide bonds. The results show that a shampoo with quaternized wheat proteins hydrolysate possesses excellent properties in recovering damaged hair, making the surface of hair smooth and compact.

The effect of autoclaving on soluble protein composition and trypsin inhibitor activity of cracked soybeans

The effects of autoclaving conditions (heating for 5, 10 and 15 minutes at 0.5 bars over pressure) and oil-extracting temperatures (40?C, 60?C) on protein content, composition, and inhibitor activity of cracked soybeans were investigated. The results obtained indicated that oil-extracting method and heat treatment had significant influence on soluble protein content and composition. Raw soybean samples defatted at lower temperature had better solubility (535.42?2.10 mg/g) than those obtained by the Soxhlet procedure (345.53?2.80). The same results were obtained for nitrogen solubility index. Autoclaving combined with two oil-extraction methods decreased protein solubility to 180.32?1.50 -245.41?1.41 mg/g, while the dominant component of heat treated flours was 11S fraction. High content of glycinin fraction (44.59-41.10%) implies the possible use of treated samples in food industry. Residual activity of treated samples was 43.40-84.26%. Kunitz inhibitor (KTI) was responsible for residual inhibitor activity.

An improved method for determining the nitrogen solubility of caseinates

SummaryThe nitrogen solubility index (NSI) method for the examination of caseinates was evaluated. It was found that widely scattering NSI values are mainly due to ineffective centrifugation and filtration of the caseinate dispersion. In order to avoid this, an improved combined centrifugation–filtration procedure was developed as an alternative to the original NSI method, using an Amicon micropartition system MPS-1 equipped with discs of filter paper. The micropartition devices can be centrifuged in a Gerber centrifuge of the type used for butyromctric fat determination. Several types of caseinates were evaluated with the new method and yielded a markedly smaller range of single values than were obtained with the NSI method.