Evaluation of some quality parameters of minimaly processed celery by quantitative analysis

Abstract

The celeries were treated with citric acid (1.5%) and L-cysteine (0.5%) following preprocessing. The samples were packed in two different modified atmosphere conditions. After 20 days of storage at 42C, weight loss, total dry matter, total acidity, total phenolics, ascorbic acid, total carotenoids, color, polyphenoloxidase (PPO) and antioxidant activity of the samples were determined, and total bacteria and total coliform were counted. At the end of the storage period, antioxidant activity was decreased as 26.23%. Generally, citric acid treatment with N-2 and CO2 atmosphere application was more effective than L-cysteine treatment for preservation of phenolic compounds. The L-cysteine-treated samples had the minimum PPO activity and were also preferred by panelists according to color criteria. During storage period, because of oxidation of conjugated bond, carotenoids were oxidized and decreased by approximately 45.61%. Weight loss of the modified atmosphere packaging celeries during storage period was changed between 0.18 and 0.32%. The samples treated with L-cysteine preserved their original color until the 10 days of storage, but the same samples were rejected by panelists for odor criteria. The big positive correlation coefficients showed was that the ratio of positive interactions was more than negative interactions. For this reason, lots of analytical criteria determined in celery increased with the increment of the other criteria. According to the results of the cluster analysis, analytical criteria were gathered in three main clusters. PPO activity element represented the first factor and antioxidant activity variable represented the second factor.

PRACTICAL APPLICATIONSCelery is a popular ingredient of prepared soups and salads. Unfortunately, this vegetable is highly perishable and is therefore difficult to store in a fresh state for an extended period of time. In order to extend the shelf life of celery, several treatment methods are used to inactivate enzymes and kill pathogens and other microorganisms that may result in spoilage. The main contribution of this work was to determine the effect of different treatment on the quality attributes of minimally processed celery stored at 4 +/- 2C for 20 days. For this reason, two different solutions (citric acid and L-cysteine) were used for following preprocessing. The samples were packed in two different modified atmosphere conditions. Physicochemical and microbiological analyses were done during storage. For statistical evaluation, factorial analysis with principal component and cluster analysis were used. The proposed procedure involves several analyses for dimension reduction of data that are conducted by principal component analysis.