Effect of Ultrahigh Pressure Sterilization on Nutritional Composition of Fresh Juice.
The ultra-high pressure cold sterilization method is to mix the water containing solid food raw materials, fill them into a soft vacuum bag for sealing, and then enter thousands of hydrostatic pressure ultra-high pressure sterilizers for pressure treatment; Fluid juice does not need to be directly packaged to autoclave for cold sterilization. Under hydrostatic pressure, food changes to the direction of its own volume reduction, that is, hydrogen bonds combine to form a three-dimensional structure of biopolymer, ion binding, hydrophobic binding and other non common reactions. The result is that life activity stops, protein denaturation, starch burning, enzyme activity loss, microbial and bacterial destruction and death; On the contrary, the binding of protein and amino acid did not change at thousands of atmospheres; Vitamins, aroma components and other low-molecular-weight compounds also have a common combination, which has not changed under high pressure.
After being processed by ultra-high pressure food sterilization equipment, it was found that the benzaldehyde content in fresh peaches increased, γ- The content of lactone changed little. Ultrahigh pressure treatment had an effect on the aroma components, but there was no significant difference in sensory evaluation. After ultra-high pressure treatment, the esters of strawberry, banana, apple and pineapple in the typical fruit aroma simulation system will have an impact. The color and aroma of fresh fruit and vegetable juice are greatly affected by the residual enzymes in the ultra-high pressure fruit and vegetable juice.
Ultrahigh pressure can activate or inactivate enzymes in food, such as catalase, polyphenol oxygenase, pectin methylase, lipoxygenase and cellulase, and affect food quality. The results showed that the methylesterase in fresh orange juice could be completely inactivated by pressure treatment of 200~400 mpa at room temperature. The methyl esterase in orange juice was irreversibly inactivated by 99% under 600 mpa pressure. PPO of grapes, strawberries, apricots and apples is sensitive to pressure, and it is found that although ultra-high pressure has the effect of inactivating enzymes, its effect is not as good as heat treatment. By evaluating the activity of residual enzymes in ultra-high pressure treated fruit and vegetable juices and their effects on the color and aroma of products during cold storage, the indicators of residual enzyme activity of products can be reasonably formulated to control product quality.