The effect of high hydrostatic pressure processing on the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices

Anthocyanins and flavonols are types of phenolic compounds. Previous researches showed that phenolic compounds are relevant to the quality of plant-derived foods and beverages. Any food-processing technologies, which can preserve phenolic compounds after processing, should be taken into account for increasing the food quality. High hydrostatic pressure processing (HHPP) is a novel nonthermal process. There are some researches about the effect of HHPP on total phenolic content, total monomeric anthocyanins, kaempferol, myricetin and quercetin contents of berry fruits and berry juices in the literature. These studies showed that HHPP could possibly have a success potential in increasing the extraction, retention and stability of anthocyanins and flavonols contents of berry fruits and berry juices by preserving phenolic compounds after food processing. The aim of this review is to put forward how high hydrostatic pressure processing affects extraction, retention and stability of anthocyanins and flavonols of berry fruits and juices

Effect of high hydrostatic pressure on physicochemical and biochemical properties of milk

Interest in high hydrostatic pressure (HHP) applications on milk and dairy products has recently increased as HHP offers a new technology for food preservation to the food industry. Although HHP-induced microbial destruction, rennet or acid coagulation of milk and increase in cheese yield has been reported, the actual effect of HHP application on milk constituents still remains to be unexplained. Therefore, we have analyzed the effect of HHP on physicochemical and biochemical properties such as turbidity, pH and especially protein micelle surface hydrophobicity of milk proteins. To serve for this purpose, milk samples with different fat contents were pressurized from 110 to 440 MPa at 25 degrees C for 10 and 20 min. Turbidity decreased with pressure increase and there was a slight change in pH. In order to measure the extent of exposure of hydrophobic groups of proteins to HHP, the method described by Bonomi et al. [1], based on use of a fluorescent probe, was utilized. In the light of the results obtained, it can be concluded that HHP has an effect on non-covalent interactions and especially hydrophobic bonds in milk. As the pressure is increased from 110 to 440 MPa, the micelles possibly decompose into sub-micelles and the embedded hydrophobic areas inside these micelles re-position in such a way that they can readily interfere with the fluorescent marker, ANS. These results may lead to practical applications of HHP treatment in the dairy industry to produce microbiologically safe, minimally processed products with high nutritional and sensory quality and novel texture