EFFECT OF PRE-TREATMENT AND MODIFIED ATMOSPHERE PACKAGING ON QUALITY ATTRIBUTES AND VOLATILE COMPOSITION OF POMEGRANATE ARILS ('BHAGWA')
A major problem associated with minimally processed pomegranate arils (Punica granatum L.) is the development of off-odours and microbial growth when stored under modified atmosphere packaging (MAP) at high CO2 and low O2. This study investigated the effects of passive-MAP combined with anti-browning pre-treatment (4-hexylresorcinol (0.001 M) + potassium sorbate (0.05 M) + ascorbic acid (0.5 M)) on the microbial quality and change in volatile composition of pomegranate (Bhagwa) arils stored at 5°C for 15 days. Changes in headspace gas composition, physicochemical attributes, volatile composition and microbial quality were evaluated at 3-day intervals for 15 days. Volatile compounds were extracted via headspace solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Headspace gas composition was significantly influenced by pre-treatment, packaging and storage duration (p<0.05), across all treatment. A decrease in total soluble solids (TSS), titratable acidity (TA) (0.3-0.4 g citric acid (CA) 100 ml-1) and pH (2.6-3.4) was observed across all treatments. Anthocyanin concentration varied with storage duration and treatment, however, an increase was observed with reference to initial concentration (12.8±0.5 mg cyanidin-3-glucoside (C3gE) 100 ml-1). Yeast and mould counts ranged from 1.5-4.9 log CFU g-1 after 12 days of storage. Pre-treatment and passive-MAP helped maintain produce quality attributes and delayed microbial growth compared to clamshell trays. Furthermore, compositional changes in volatile compounds were identified from GC-MS analysis. A total of 13 primary and 28 secondary volatiles were detected and identified in the headspace of pomegranate juices of Bhagwa.
Caleb, O.J., Aindongo, W.V., Opara, U.L. and Mokwena, L. (2015). EFFECT OF PRE-TREATMENT AND MODIFIED ATMOSPHERE PACKAGING ON QUALITY ATTRIBUTES AND VOLATILE COMPOSITION OF POMEGRANATE ARILS ('BHAGWA'). Acta Hortic. 1079, 165-171
off-odour, anthocyanin, microbial stability, postharvest quality, packaging