, & Artz, E. W. (1988): Twin-screw extrusion as a continuous pre-treatment process for the enzymatic hydrolysis of cassava. J. Fd. Set , 53 , 1792-1799.
Twin-screw extrusion as a continuous pre-treatment process for the enzymatic
Authors:A. Keles, Y. Dogruer, G. Ucar, and A. Guner
In this study, Halloumi cheese samples were produced from preacidified cow's milk. Glucono-delta-lactone (gdl), lactic, citric and acetic acids were used in preacidification treatments. The cheese samples were vacuum packed and ripened at 7±1 °C for 90 days. The changes in some chemical, microbiological and sensory properties of the Halloumi cheese samples were investigated during the ripening period. Gdl and lactic acid were found more suitable than citric and acetic acids as an acidulant in Halloumi cheese production
hypertrophy in its active form and is sought to be completely inactivated in soy products.Several processing methods like heating, extrusion, sprouting, or combinations of these treatments are employed by soy food industry to inactivate KTI ( Dia et al
Managing waste becomes a much more complex task, when logistic changes have to be implemented to combine selective waste collection, needed to increase the rate of recycling, with traditional residual waste collection. This complexity is complicated further by the ever increasing choices of methods and technologies available for the treatment of collected waste.Using available resources efficiently, minimizing environmental effects and operation costs should be the guiding ideas behind optimization of a waste management system, even though often these ideas are in conflict with each other. In this phase of research those factors which have a major influence on system costs are analyzed.
A welded steel protective cover used for the heat treatment of steel sheet coils is investigated. The protective cover is made of austenitic stainless steel and consists of three main segments, welded together, which have 1400 mm height each. The plate thicknesses at the lower, middle and upper segments are different. The investigation aimed to improve the lifetime and the number of heat cycles of the protective cover by changing the geometry, the effect of the thicknesses and the material. Damaged covers have been evaluated, made calculations of stress and deformations, and carried out a series of finite element simulations. Both horizontal and vertical corrugated sheets were simulated and compared. The non-corrugated plates were also investigated, but their performance was behind the corrugated ones. The original geometry and that of the horizontal corrugated plate are identical from the stress level point of view. The vertical position of the corrugated plate provided a better result than the horizontal one. The calculated and simulated results for the original geometry are close to the measured damage.
Protein hydrolysis using immobilized proteases may present problems, which are mainly caused by the diffusion of macromolecular substrate. Pre-hydrolysed substrate could be a viable alternative in this process. The aim of this work was to test the casein and β-lactoglobulin hydrolysis using immobilized papain on glyoxyl-agarose, following substrate pre-treatment with immobilized trypsin. Although immobilized papain showed difficulties to degrade the milk proteins, after 10 min of trypsin pre-hydrolysis, the immobilized papain was able to achieve the maximum degree of hydrolysis in shorter time. For pre-hydrolysate casein, the immobilized papain reached 98.9% at 60 min total reaction (including the 10 min pre-digestion). As for β-lactoglobulin, immobilized papain was capable of achieving maximum levels after just 60 min of reaction, where the free enzyme only achieved 60% of its maximum. Pre-hydrolysis with trypsin appears to have worked well as a pre-treatment method to increase the proteolytic action of immobilized papain.
Authors:S. Dragoev, D. Balev, G. Ivanov, B. Nikolova-Damyanova, T. Grozdeva, E. Filizov, and K. Vassilev
Lipid oxidation is one of the main factors responsible for the quality loss in refrigerated and frozen stored fish products. The aim of the study was to evaluate the effect of superficial treatment of Atlantic salmon (Salmo salar) with dihydroquercetin (DHQ) solutions on the hydrolytic and oxidative changes in fish lipids during refrigerated storage. It was found that treatment with DHQ solution (1.0 g l−1) reduced approximately twice the free fatty acids content of chilled stored salmon. After 11 days of storage at 1 °С, the contents of hydroperoxides (HPO) and 2-thiobarbituric acid reactive substances (TBARS) of these samples decreased with 45.00 and 0.91 mg MDA/kg, respectively. The share of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) in control and experimental samples did not differ significantly (P>0.05). Results obtained show that the superficial treatment of salmon with DHQ solution (1.0 g l−1) delayed the hydrolytic and oxidative changes in fish lipids significantly, thus preserving the salmon freshness up to 11 days of storage at 1 °С.
The effect of organic acids on the melanosis inhibition and shelf-life on shrimp was investigated. Shrimps were treated with 1% solutions of lactic, citric, acetic acids, sodium metabisulfite (0.3%) and their various combinations. After treatments the shrimps were stored at 4 °C and evaluated for melanosis every day and quality changes on every other day. Combinations with sodium metabisulphite were the most effective in delaying melanosis. Citric and lactic acids extended shelf life to a lesser extent but acetic acid had no effect.