Pengaruh Penambahan Asam Sitrat Terhadap Proses Non-Enzimatik Browning Jus Buah Pir Yali (Pyrus bretschneideri Rehd.)

Abstract

The purpose of this study was to find out how effective citric acid is against the nonenzymatic

process of browning Yali Pear fruit juice (Pyrus bretschneideri Rehd. The
research was conducted in a complete randomized design consisting of 5 replications. The
non-enzymatic browning inhibition process was tested with citric acid treatment as the main
factor with five concentrations ie 0% w/v, 2,5% w/v, 5% w/v, 7,5% w/v and 10% w/v.
Qualitative parameters were dehydrogenase enzyme activity and reducing sugar level.
Quantitative parameters were browning index and total soluble carbohydrate content.
Levene test, analysis of variance, and Tukey test were performed at 5% significant level. The
results showed that decrease in dehydrogenase enzyme activity occurs along with increasing
the concentration of citric acid. The level of reducing sugar has increased along with the
increase of citric acid concentration. The 7,5% w/v citric acid concentration effectively
inhibited non-enzymatic browning of Yali Pear juice with a 21% reduction in the browning
index. Total soluble carbohydrate content increased 7% at 7.5% w/v citric acid
concentration. From the results of the study it was concluded that citric acid at 7,5% w / v
concentration was the inhibitor of non-enzymatic browning and dehydrogenase enzyme
activity, but stimulator of total soluble carbohydrate and reducing sugar level.