Changes in the composition of tomato powder (Lycopersicon esculentum Mill) resulting from different drying methods

Heating drying processes may cause undesirable changes in tomato composition and loss of quality, mainly in bioactive components. The objective of the study was to evaluate the effects of oven drying, heated air flow, and freeze-drying on blanched and unblanched tomatoes. This allows choosing drying conditions with less undesirable changes. The contents of sugar, citric acid, ascorbic acid, lycopene, -carotene, and total phenolic compounds, and 5-hydroxy-2-furaldehyde (HMF) formation were evaluated. Results revealed that samples with lower sugar content also showed higher level of HMF. The heated air flow lead to low HMF formation, low reduction of sugar and a higher concentration of lycopene, -carotene, phenolics, and ascorbic acid. Freeze drying lead to low levels of carotenes in the end product. In conclusion, fractions of lycopene, -carotene, phenolics were increased by blanching, and losses of sugars, HMF, ascorbic acid were related to blanching. Practical applicationsThe actual applications of this research are to evaluate the behavior of bioactive components in tomatoes that underwent different drying methods. Different processing parameters may lead to undesirable changes in composition of tomatoes and cause loss of quality in dried products. The potential applications are to evaluate which parameters are capable to maintain the higher quality levels in the end product.