The effect of high hydrostatic pressure on anthocyanins and ascorbic acid in blackcurrants (Ribes nigrum)

The stability of two anthocyanins and ascorbic acid present in fruit juices made from blackcurrants that were subjected to high-pressure processing (HHP) was studied. HHP is a non-thermal food preservation method and its impact on the nutritionally important anthocyanins, cyanidin-3-rutinoside, delphinidin-3-rutinoside and also ascorbic acid (vitamin C), in blackcurrants was assessed. Fruit samples were treated at 200, 400, 600 and 800 MPa for 15 min under controlled temperature (20-22.5 °C). After high-pressure treatment the samples were stored at fridge temperature (5 °C), room temperature (20 °C) and at 30 °C. The analysis of the anthocyanin and ascorbic acid contents were carried out by using high performance liquid chromatography (HPLC). The best stability for cyanidin-3-rutinoside pigment was found when blackcurrants were treated at a HP of 600 MPa and were stored at 5 ° C. Delphinidin-3-rutinoside had the lowest losses when treated at 800 MPa and stored at 5 °C. High pressure at 600 MPa gave the best preservation for all the samples stored at 5 °C and 20 °C. The rates of losses observed for anthocyanins were linked to those observed for the ascorbic acid and these results are discussed. Copyright © 2004 John Wiley & Sons, Ltd

Effect of pH on Color and Texture of Food Products

[EN] Color and texture are important quality characteristics and major factors affecting sensory perception and consumer acceptance of foods. pH has an important effect on pigments (e.g., chlorophyll, carotenoids, anthocyanins, etc.) responsible for fruit color, vegetables and meat color. Also pH has a great impact on water-holding capacity and tenderness of muscle foods that are improved at acidic conditions below the typical pH of post-mortem. Moreover, during processing of food, the pH value affects many phenomena and processes such as protein properties as denaturizing, gelification, enzymatic activities, growth and mortality of microorganisms, germinating or inactivation of bacterial spores and chemical reactions such as the Maillard reaction. Thus, knowledge of pH effects and its control during processing is necessary to produce safe, high-quality and value-added products. 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