Food Technology
Mohammad Ali Hesarinejad; Atefeh Arefkhani; Ali Rafe; Fatemeh Javidi; Alireza Sadeghian
Abstract
Introduction: Improving the texture and sensory properties of Iranian white cheese by reducing fat content is one of the most important issues that are considered both technologically and economically. Meanwhile, controlling the amount of water absorption in cheese usually causes textural problems in ...
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Introduction: Improving the texture and sensory properties of Iranian white cheese by reducing fat content is one of the most important issues that are considered both technologically and economically. Meanwhile, controlling the amount of water absorption in cheese usually causes textural problems in cheese, including the softness of the cheese texture. Therefore, this problem will be solved if the amount of water absorption in the cheese can be controlled in such a way that the resulting cheese texture does not change and even its quality improves. Currently, the demand for the use of compounds or methods to achieve this goal is increasing. Hydrocolloids are compounds that, due to their inherent nature in absorbing water and creating a mouth-feel like fat, can have a special effect on fat replacement. Therefore, creating a suitable formula in the composition of hydrocolloids can complement the qualitative improvement of cheese texture. Basil seed gum (BSG) is a native hydrocolloid that has shown good stability and emulsifier properties, making it a potential functional ingredient in the food industry. Xanthan gum (XG) is also used in food as a thickener and stabilizer, and also can acts as a gelling agent along with other gums. In this study, by creating a suitable formulation in the use of these hydrocolloids, an attempt is made to improve the texture and sensory properties of cheese. Materials and methods: The effect of different concentrations of mixed-hydrocolloids based on XG/BSG, and Guar gum (GG)/BSG on the textural attributes of Iranian white cheese was investigated. Four cheese treatments (without hydrocolloids or with 0.25, 0.5, or 0.75 g/kg of milk) were produced to study the effects of hydrocolloid content on the textural properties of the product. Cheese samples were analyzed with respect to physicochemical, color, sensory characteristics, textural properties, and microstructure. Results and discussion: The results showed that the higher concentration of hydrocolloids from 0 to 0.075% used, the higher the increasein the moisture content of cheese samples. The results also showed that samples containing GG had higher moisture content than samples containing XG, which is probably due to the higher water absorption capacity of GG than XG. Increasing the concentration of hydrocolloids reduces the fat in the sample, which is due to the absorption and retention of more water in the cheese due to the hydrophilic properties of hydrocolloids. Samples containing GG had a lower fat content than samples containing XG. As the concentration of hydrocolloids increased, lightness increased, indicating the effect of hydrocolloids on the increase in whey cavities. The results also showed more lightness of XG samples than GG samples. Samples containing XG were more rigid, possibly confirming that this hydrocolloid has a greater effect than a mixture containing GG in the strength of the cheese and the effect of the GG is merely thickenning. With the increase in the concentration of BSG/XG (from 0.025 to 0.075%), the hardness increased from 260.96 to 364.23 g. The springiness of all samples also ranged from 0.99 to 1 mm, indicating good reversible behavior. It was found that the formula containing BSG/XG at a concentration of 0.50% had the highest overall acceptance after the sample containing BSG/XG at a concentration of 0.075%. Samples containing gum had low sensory evaluation results, possibly due to high moisture content, and were reported to be undesirable. In terms of taste, the samples did not differ significantly from each other. According to the results of textural analysis and sensory evaluation, the formula containing BSG/XG at 0.075% concentration, due to having the highest score of sensory evaluation and desirable textural characteristics, was selected as the optimal sample. In the microstructure of the desired cheese sample, the location of the whey serum has been determined. By adding hydrocolloid to the cheese, the protein matrix opens. When the sample was prepared for SEM analysis, the moisture was removed. Therefore, the effect of hydrated hydrocolloid was observed in the form of cavities. This structure has enough space to trap water and form a suitable gel.
Alireza Sadeghian; Reza Mesgarian
Abstract
Probable use of chemical and biochemical detergents to wash polysulphone membranes using in milk ultrafiltration needs a multidisciplinary investigation. By increasing use of these membranes in food processing, washing and recovery of initial permeate flux, in order to use for a longer time from this ...
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Probable use of chemical and biochemical detergents to wash polysulphone membranes using in milk ultrafiltration needs a multidisciplinary investigation. By increasing use of these membranes in food processing, washing and recovery of initial permeate flux, in order to use for a longer time from this technology, has much importance. In this research, influence of chemical detergents including EDTA, SDS and NaOH, biochemical including protease and lipase on recovery of permeate flux of ultrafiltration from polysulphone amide with pore size of 20 kD as a function of temperature, pressure, and time were investigated. Optimum amounts of activity of Protease and Lipase in temperature, pH and time of incubation were measured. Results showed that lipase cannot recover permeate flux and usefulness of this enzyme is not comparable with protease. With respect to the results obtained about optimum concentration of enzymes in recovery permeate flux, optimum concentration of chemicals in washing polysulphone membrane including EDTA, SDS, and NaOH were measured. Also, efficiency of optimum rate to mix enzyme, SDS and EDTA to recover flux and chemical used in industry were evaluated. Results showed that biochemicals (enzymes) are able to recover at least 60% of initial flux membranes. This rate for chemicals and under continuous and turbulent flow has been reported to be more than 95%.
Key words: Ultrafiltration, Permeate flux, Pulysulphone membranes, Chemical & biochemical detergents
