RELATIONSHIPS AMONG TITRATABLE ACIDITY, pH AND BUFFER COMPOSITION OF TOMATO FRUITS

Abstract

Relationships among pH, titratable acidity (TA) and buffer composition of tomato fruits were studied using analytical data, from 25 divergent accessions, and from previous work. Citric and malic acids, and phosphate account for about 93% of the TA of tomatoes. An increase in phosphate concentration results in a decrease in [H+], whereas an increase in citric and malic acids increases [H+] These relationships probably exist because of differences in the origins of phosphate and the two acids. Variation in phosphate concentration can be of practical value in efforts to maintain a safe processing pH in low sugar, low acid varieties because phosphate has a relatively large effect on [H+] with a minimal effect on TA.

Characterization of Determinate Tomato Hybrids: Search for Better Processing Qualities

“…Citric acid is the most abundant acid in tomatoes and the largest contributor to the total titratable acidity [23]. The acidity of the fruit is also important as a contributor to the flavour of the tomato products.…”

Quality attributes of processed tomato products: A review

“…The sample is put into the cone and the amount of serum drained in a given time is a measure of the serum-holding capacity of the product. Acid concentration and pH are important quality and processing characteristics of tomatoes (136). In addition to flavor and consistency, they influence the processing time and temperature of the products.…”

“…Practically all foods contain an acid or a mixture of acids which may be either present naturally, produced by microorganisms, or added to the food during processing. Both [H + ] and potential acidity contribute to tartness in the food (136). Generally, the acid concentration in tomatoes increases during development, reaching maximum near incipient color; thereafter, the acid content decreases (12).…”

“…In such a system the more acidic a product is, the easier it is to control the asepsis (119). The pH should be lower than 4.4 to avoid problems with thermophilic organisms (136). The pH influences the consistency of tomato products by modifying the total pectin content and pectin characteristics.…”

Physico-Chemical Evaluation of Fruits from the Fourth Filial Generation of Some Breeding Lines of Tomatoes

“…pH values are crucial for processing tomatoes since values higher than 4.4 indicates susceptibility of the pulp to thermophilic pathogens [13]. Thus, pH values as low as possible (up to the point that it does not adversely affect taste) should be bred into tomato cultivars for industrial use [14].…”