Abdolkhalegh Golkar; Ali Nasirpour; Javad Keramat
Abstract
Introduction: Hydrocolloids are widely used in food systems as an emulsifying or stabilizing agent. One way to improve the emulsifying properties of hydrocolloids is complexation with proteins. In general, protein and hydrocolloid components may be combined together by either A) covalent bonding (conjugates) ...
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Introduction: Hydrocolloids are widely used in food systems as an emulsifying or stabilizing agent. One way to improve the emulsifying properties of hydrocolloids is complexation with proteins. In general, protein and hydrocolloid components may be combined together by either A) covalent bonding (conjugates) or B) electrostatic complexing. Conjugates can be efficiently prepared during the storage of freeze-dried or spray-dried powders of protein- hydrocolloid mixtures if stored at appropriate temperature and relative humidity. Farsi gum (FG) is a natural gum that exudated from mountain almond trees (Amygdalus scoparia Spach). In this study, BLG (β-lactoglobulin)-FG conjugates were prepared by dry heat treatment at different BLG/FG mixing ratios (1:1, 1:2 and 2:1) and emulsifying properties of these conjugates were characterized. Materials and methods: Firstly, BLG and FG were dry mixed at BLG/FG (1:1, 1:2 and 2:1) weight mixing ratios. The BLG-FG mixtures were incubated at 60 ºC for a period of 1-14 days in desiccators containing saturated NaCl (to have 75 % relative humidity). Formation of BLG-FG conjugates was confirmed by SDS-PAGE. With the advancement of Maillard reaction, Amadori and browning compounds formation was determined by the absorbance at 304 nm and 420 nm, respectively. Creaming Index (CI) was assessed by determining the height of serum layer developed during storage (at 30 min intervals for 180 min) in emulsion (0.5 wt. % total biopolymer and 25% v/v O/W). The emulsion activity index (EAI) and emulsion stability index (ESI) were determined by turbidimetric technique at 500 nm absorbance. In addition, the effect of storage (3 days) at accelerated condition (40 ºC) and freeze-thaw treatment on droplet size distribution of emulsions (1.5 wt. % total biopolymer and 40 % v/v O/W) were evaluated by static light scattering. Finally, microstructure of BLG-FG emulsion was captured by light microscopy. Statistical analysis of the all data was carried out using SAS 9.1 with significance defined at P0.05) effect on EAI. However, ESI was significantly increased over time and ESI of 2-week incubated BLG-FG conjugate was significantly different (P
Elnaz Ghasemtabar; Amir Hossein Goli; Ali Nasirpour
Abstract
Milk and fruit juice due to the high nutritional value, are widely consumed by society’s people. Pomegranate juice in spite of nutritional value has oldness in consumption and milk-pomegranate juice product could be desirable specifically for the consumers who are keen to experience new formulation ...
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Milk and fruit juice due to the high nutritional value, are widely consumed by society’s people. Pomegranate juice in spite of nutritional value has oldness in consumption and milk-pomegranate juice product could be desirable specifically for the consumers who are keen to experience new formulation and taste. Milk-juice beverage is a type of acidified milk drink that one of the main problems in production of the beverage is its low pH. In this study, in order to optimize the milk-pomegranate juice beverage formulation, three factors of milk, pomegranate juice and pectin content were selected. Formulation optimization and determination of optimum levels of each factor was carried out using response surface methodology (RSM) and to study the effect of storage time, optimum milk-pomegranate juice formulations were stored in refrigerator for 42 days and their physicochemical properties were evaluated. The results showed that the effect of milk and pectin content and factors interaction were significant on sedimentation and separation responses. The treatment of 50% pomegranate juice, 20% milk, 30% water and 0.63% pectin had the most nutritional value and can be recommended to be produced. The results revealed that production of milk –pomegranate juice beverage without any sedimentation and seperation by using pectin as stabilizer is possible and the product storage in the refrigerator had no negative effect on its nutritional value.
Zahra Izadi; Ali Nasirpour; Ghasem Ali Garoosi
Abstract
Phytosterols have been used for reduction of cholesterol since 1950. The high melting temperature and chalky taste are the major problems related to the enrichment of foodstuffs with phytosterols. The Cristal construct of these compounds could not reduce remarkably the blood cholesterol in comparison ...
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Phytosterols have been used for reduction of cholesterol since 1950. The high melting temperature and chalky taste are the major problems related to the enrichment of foodstuffs with phytosterols. The Cristal construct of these compounds could not reduce remarkably the blood cholesterol in comparison with the fatty soluble forms. Presence of free and alcoholic forms of phytosterols and also their capability in making strong linkage with nutritional matrix make difficult and complicate their analysis and distribution quality in foodstuffs. In this study the emulsion include the emulsifier, soy bean oil and water was used for dissolving and dispersing of phytosterols in water phase. Then the distribution state of phytosterol in enriched yogurt was investigated using Gas Chromatography. Because of the appearance and color are the first parameters in the evaluation of nutrition materials, digital imaging and Photoshop software was used to measure the color of enriched yogurt. Results indicated that the using of emulsifier and soy bean oil could be suitable approach to disperse and dissolving phytosterol in liquid phase. Gas Chromatography showed that it is a favorite method to measure manner of dispersing the phytosterol. In the colorimetric studding no significant differences observed between enriched yogurts and control. Also result exhibited that the using of Photoshop software could be the better scale in comparison with the other current method and instruments for color assay of the yogurt.
Ghasem Ali Garoosi; Ali Nasirpour; Jafar Ahmadi; Bahman Bahrami
Abstract
Hypercholesterolemia is major risk factors for heart disease. Plant sterols have been used for reduction of cholesterol since 1950 decade; so enriching food materials with such components is important. Major problems related to enrichment of products with plant sterols are high melting temperature and ...
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Hypercholesterolemia is major risk factors for heart disease. Plant sterols have been used for reduction of cholesterol since 1950 decade; so enriching food materials with such components is important. Major problems related to enrichment of products with plant sterols are high melting temperature and chalky taste. In addition, crystal form of these components in comparison with lipid-in solved forms can not significantly reduce the blood cholesterol. In this study enrichment of yogurt and optimization of the process condition were investigated. A four components (plant sterols, emulsifier, vegetable oils and water) mixture design was used to define the percentage of each mixture component to simulate wide range of mixture with different oil quantities. Emulsifier and soy oil were used for dissolving and dispersing of plant sterols in water phase. Yogurt texture, syneresis susceptibility, acidity and viscosity were measures during storage. Gel strength of enriched samples was higher than control. The mean values of syneresis and viscosity of enriched yogurts with phytosterol, were significantly (P < 0.05) lower than the control yogurt. Addition of plant sterol into yogurt did not change titrable acidity. Taste and flavor tested by panelists, where enriched yogurt was preferred to control.
Keywords: Cholesterol, Plant sterol, Yogurt, Emulsion
