Effect of perforated blue polyethylene bunch covers on selected postharvest quality parameters of tissue-cultured bananas (Musa spp.) cv. Williams in Central Kenya

Abstract

Banana farming in Kenya has recently moved from subsistence to commercial farming. There is therefore the need to produce high quality fruits that are visually acceptable, have good postharvest quality attributes and therefore sell well in both local and international markets. Technologies such as pre-harvest bunch covers have been shown to improve postharvest quality of banana fruits. However, earlier reports on the effect of bunch covers on postharvest quality of banana fruits in the tropics have been contradictory. This study therefore aimed at understanding the effect of perforated polyethylene bunch covers on the postharvest quality characteristics of tissue-cultured bananas using banana (Musa spp.) cv. Williams as the test variety. The trial was carried out in Maragwa region in central province of Kenya, in a complete randomized design and was replicated three times. Perforated dull and shiny blue polyethylene covers were placed when the hands had started to turn upwards. Fruits were harvested at full three quarter maturity. Parameters measured were; bunch weight, finger grade and length, starch, total soluble solids (TSS), sugars, total titratable acidity (TTA), pulp/peel ratio, colour, chlorophyll content, firmness, moisture content, weight loss, green life and shelflife. Banana bunches were also evaluated for cleanliness and bruise marks at harvest. Data were subjected to analysis of variance (ANOVA) using the general linear model (GLM) procedure of SAS statistical programme. The means were compared using Student Newman Keuls’ test (SNK) and least significant difference (LSD) at significance level of 5%. Results showed that bunch covers did not influence finger grade, length and bunch weight at harvest. Colour, chlorophyll content, firmness, starch content, TSS, TTA, moisture content, weight loss, individual and total sugars and pulp/peel ratio at harvest and during ripening were not influenced by bunch covers. Bunch covers did not influence greenlife and shelflife significantly. Fruits grown under cover were more visually appealing, cleaner and had minimal bruises compared to the unbagged fruits. However, bunch covers had some detrimental effects on postharvest quality characteristics of banana fruits of the covered bunches compared to the fruits from the control, where few fingers of top hands of some bunches suffered sun burn. The study has shown that perforated dull and shiny blue bunch covers may be used in commercial banana orchards in Kenya to produce high quality fruits especially in the cooler areas.

Key words: Musa spp, polyethylene bunch covers, postharvest quality.