Relationship between the bagging microenvironment and fruit quality in ‘Guibao’ peach [Prunus persica (L.) Batsch

Abstract

SummaryThe late-ripening peach [Prunus persica (L.) Batsch] cultivar ‘Guibao’ was chosen in order to study the effect of different bagging treatments on the appearance, skin quality, and internal quality of fruit. Diurnal variations in temperature and relative humidity (RH) in white single-layer paper bags (WPB), white single-layer polypropylene non-woven bags (WPPB), and black single-layer paper bags (BPB) were recorded for 15 d before harvest. Bagging treatments were applied 30 d after full bloom (DAFB). The WPB and WPPB treatments continued until harvest, while the BPB were removed 7 d before harvest. Observations were recorded on skin colour and fruit quality attributes such as fruit fresh weight (FW), flesh firmness, total soluble solids concentration (TSSC), colour, skin pigments, soluble sugar concentrations (SSC) and organic acid concentrations. The average temperature and RH increased slightly in the bags. Compared with unbagged control fruit, the average temperature in WPB, WPPB, and BPB increased by 1.27%, 0.90%, and 0.04%, respectively. The RH in the same three types of bag also increased by 5.07%, 4.09% and 7.30%, respectively. Bagging led to higher mean fruit FW and skin lightness values. No significant differences were observed in peel anthocyanin or chlorophyll concentrations between the WPB and WPPB treatments, while the red colour saturation scale (a*) and chroma (C) values increased in the three types of bags. Anthocyanin concentrations in the peel of fruit from the BPB treatment increased rapidly to 44.52 nmol g-1 FW after bag removal. Both white bags had similar effects on fruit FWs, skin colour, pigment concentrations, and anti-oxidant capacity, as well as SSC and organic acid concentrations, but not TSSC and C values. The temperature and RH microenvironment in the bags could affect the rates of transpiration and respiration, with significant effects on SSC values. Based on these results, to obtain ‘Guibao’ peach fruit with an attractive skin appearance and good internal qualities, we recommend that fruit should be covered with bags and, if BPB are used, the bags should be removed 7 d before harvest.