Effect of different post-harvest treatments on quality of minimally processed long bean (Vigna unguiculata var. Sesquipedalis)

M. Razali and M. Habsah

Abstract

Different post-harvest treatments were evaluated on the minimally processed (MP) long bean (Vigna unguiculata var. Sesquipedalis) i.e. control (without treatment), 1% calcium chloride (CaCl₂), 1% ascorbic acid (AA; C₆H₈O₆), 1% calcium lactate (CaLac; C₃H₆O₃.1/2Ca), 1% CaCl₂ + 1% AA, and 1% CaCl₂ + 1% CaLac. Some physiological changes occurred on MP long bean during storage at 2 °C. The product was evaluated at 3 days storage interval. Quality observation was based on physical and chemical changes, rate of respiration and ethylene production. When the storage temperature (2 °C) was maintained at lower level (0 °C), the quality of MP long bean still remained good after being stored at certain storage period (2 weeks). The MP long bean treated with 1% AA showed lowest in percentage weight loss (0.037%), total titratable acidity (TTA; 0.156%) and ethylene (C₂H₄) production rate (0.116 μL C₂H₄/kg/h), compared to other treatments. However, the ascorbic acid (AA) content was highest (7.263 mg/100 g) and the pH and CO₂ concentration were slightly higher, 5.16 and 0.572%, respectively for the MP long bean treated with 1%AA compared to other treatments. There were significant differences (p <0.05) observed in pH, TTA, AA and CO₂ concentration of MP long bean with different post-harvest treatments during storage period. Minimally processed long bean treated with 1% AA was not affected by enzymatic browning and showed better quality. There were also significant differences (p <0.05) in all parameters of MP long bean with duration of storage.

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