Why does pH level matter in juice?
Try this experiment.... take some strawberry extract and add it to water (pH=7). taste it then add a small amount of lemon juice to it (pH=3)and taste again. Since fruit is acid in nature (low pH) it will not taste correct unless it is acidic. pH is a scale that measures the concentration of hydrogen ions in a solution. low pH is acidic (less than 7) and high pH (greater than 7) is basic. Some foods are naturally basic. chocolate is one of these. Add some lemon juice to some chocolate and see if you like it. Juices have a ratio of sweet to acid that is different for each juice. If the ratio is wrong people will not like it. The acid in fruit is nature's way of preserving the fruit. without the acid the juice would quickly spoil, yeast molds and bacteria wold grow on it.
you can't change the pH level of the contents no matter where you store it. storage space has air, which is composed of our standard gases--nitrogen, oxygen, hydrogen, etc. over time, molecular interference (van der Waals forces) between the "juice" and the gases can develop as part of a chemical reaction creating OH- (base) or H+ (acid) molecules as reagents. this would surely affect the pH level of juice.
first tell me what pH is pH, for those of us who skipped grade school science class and haven't discovered Google, is the level of acidity or alkalinity of a solution. The scale ranges from 0 (highly acidic) to 14 (highly alkaline). Pure water, which is neither acidic nor alkaline, has a pH of 7. To answer the original question, pineapple juice, has a pH of 3, about the same as orange juice.--tw2