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Serum Separation (serum + separation)
Selected AbstractsVISCOSITY AND QUALITY OF TOMATO JUICE AS AFFECTED BY PROCESSING METHODSJOURNAL OF FOOD QUALITY, Issue 6 2007CHARANJIT KAUR ABSTRACT Quality and viscosity of tomato juice is strongly governed by mechanical and thermal abuse during processing. The effect of processing and storage duration on the viscosity and quality parameters of tomato juice was evaluated in the present work. Tomato juice was obtained by two different methods, normal method (NM) and variable method (VM), and was heated by both conventional and microwave hot break treatments. Tomato juice was evaluated for various quality characteristics including precipitate weight ratio, degree of serum separation (DOSS), Brookfield viscosity, lycopene levels, vitamin C, phenols and antioxidant activity. Changes observed in several quality parameters during storage were statistically insignificant. The methods and processing had the greatest contribution toward viscosity, whereas storage duration had no significant effects. Viscosity parameters viz precipitate weight, DOSS and Bostwick consistency revealed that juice processed by VM was more viscous than that of NM, irrespective of the hot break processing used. Ascorbic acid and lycopene content varied significantly with mechanical methods and processing conditions. However, phenolic content and antioxidant activity remained stable. The variable process represents an improvement over the conventional by enabling tomato processors to improve the consistency of the tomato product. PRACTICAL APPLICATIONS Quartering or slicing tomatoes followed by hot break processing techniques can significantly improve the quality of tomato juice in terms of reduced degree of serum separation and precipitate weight ratio. The modified technology could be considered as a viable and economical method for small- and medium-scale tomato processors with limited resources and facilities at their disposal. [source] IMPROVEMENT OF PHYSICAL PROPERTIES OF NONFAT FERMENTED MILK DRINK BY USING WHEY PROTEIN CONCENTRATEJOURNAL OF TEXTURE STUDIES, Issue 3 2009ASLI E. OZEN ABSTRACT The use of whey protein concentrate (WPC) for the improvement of physical properties of nonfat fermented milk drink was investigated. Drinks were prepared from nonfat milk powder and WPC at different proportions. Rheological properties, serum separation and particle size of the drinks were measured. The effect of WPC on the physical properties of the drinks was evaluated by comparison with those of commonly used stabilizers, including propylene glycol alginate and locust bean gum. WPC addition caused an increase in the consistency coefficient and thixotropy and a decrease in the particle size of the samples. There was no serum separation in the sample with 2% WPC. Large unstable aggregates were observed in the sample with 3% WPC, which also exhibited the highest serum separation. WPC up to a level of 2% positively influenced the physical properties of nonfat fermented milk drink similar to stabilizers. PRACTICAL APPLICATIONS Fermented milk drinks are consumed especially for their beneficial health effects. Physical properties of fermented milk drinks influence their quality and consumer acceptability. Hydrocolloid stabilizers are used for the improvement of physical properties of fermented milk products. Whey protein concentrates (WPC) with high protein content can be used to substitute hydrocolloid stabilizers. In this study, the effect of the addition of WPC with 75% protein in place of a part of the nonfat milk powder on the physical properties of nonfat fermented milk drink with 6% dry matter was investigated. Use of an appropriate level of WPC was found to be important for obtaining a desirable effect on the physical properties of nonfat fermented milk drink. The effect of WPC was found to be comparable to those of commonly used hydrocolloid stabilizers. Use of WPC also enhances the nutritional value of the product as whey proteins have a high biological value. [source] Emulsifying properties of gelatin conjugated to pectin under alkaline conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2005Nickolaos G Diftis Abstract Gelatin,pectin mixed solution incubated under mild alkaline conditions for a period of 4 h exhibited an improvement of emulsion stability in terms of both droplet coalescence and serum separation. Application of SDS,PAGE provided evidence for gelatin,pectin hybrid formation possibly due to amide bonds between the lysine group residues of protein and the esterified carboxyl groups of the polysaccharide. The superior stabilizing properties of the heat-treated protein,polysaccharide conjugate is attributed to the enhancement of the repulsive steric forces operating between emulsion oil droplets, as a result of conjugate adsorption through their protein moiety. Copyright © 2004 Society of Chemical Industry [source] | ||||||||||