Changes in headspace volatile composition could serve as potential biomarkers of microbial quality and shelf life for MA-packaged pomegranate arils

A major problem associated with minimally processed pomegranate arils (Punica granatum L.) is the development of offodours 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 (cv. Bhagwa) arils stored at 5?C for 15 days. Changes in headspace gas composition, physicochemical attributes (total soluble solids (TSS), titratable acidity (TA) and pH), bioactive components (phenolics and anthocyanin), volatile composition and microbial quality were evaluated at 3-day interval 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 TSS, TA (0.3-0.4 g 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 C3gE 100 mL-1). Total phenolics decreased from 2281 ?+/- 423.6 mg GAE 100 mL-1 to about 1321.3?+/- 182.8 mg GAE 100 mL-1. After day 3 microbial populations shifted from yeast and moulds to predominantly yeast population. Yeast and moulds count ranged from 1.5-4.9 log CFU g-1 after 12 days of storage. Furthermore, compositional changes in volatile compounds were identified from GC-MS analysis. A total of 15 primary and 28 secondary volatiles were detected and identified in the headspace of pomegranate juices of ?Bhagwa?. Pre-treatment and passive-MAP helped maintain produce quality attributes and delayed microbial growth. Compositional and concentration (%) changes in volatile compounds were consistent with the results of microbial analysis. These findings suggest that changes in headspace volatile composition could serve as potential biomarkers of microbial quality and shelf life for MA-packaged pomegranate arils. ? Original title, complete list of authors and sourcesEffects of pre-treatment and modified atmosphere packaging on quality attributes and change in volatile composition of pomegranate arils (cv. Bhagwa)O.J. Caleb1, W.V. Aindongo1, L. Mokwena2, U.L. Opara11Postharvest Technology Research Laboratory, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa2Central Analytical Facilities, Mass Spectrometry Unit, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa V Postharvest Unlimited, ISHS International Conference, 10-13 June 2014, Cyprus, http://web.cut.ac.cy/postharvest/ The picture is by www.tikagroup.com ? Key wordsPoscosecha?? ?postcosecha?? ?postharvest?? ?na-oes?? ??? ??? ???????? ????? ??? ?post-r?colte?? ????? ?? ??????????? ??? ?na-oogst?? ?post-raccolta?? ?Obr?bka po?? ?p?s-colheita?? ????????????????? ?hasat sonras??? ??? ?Ernte?? ????????????????? ????? ????????????? ?postcollita?? ?poskliz?ov頠 ????? ??? ??? ??? ?nakon branja?? ?pozberov頠 ??? ?obdelovanje zemlje po?? ?post-colleita?? ?????? ??????? ?pascapanen?? ??il?onn postharvest?? ??????? ?p?c ra?as?? ?derliaus apdirbimas po?? ?lepas tuai?? ??? ?? ???????? ?post-recoltare?? ??????? ??????? ???????????????????? ?????????????? ?????????????????? ?sau thu ho?ch?? ?????????????????? ?zangemva kwenkathi yokuvunaGranada?? ??? ?pomegranate?? ?granaat?? ????????? ????? ??? ?grenade?? ??????? ??????? ??? ?melagrana?? ??? ?rom㠠 ????????? ?nar?? ??????? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ????