Effect of different coating formulations with polysaccharide/protein mixture ratio for the preservation of lulo (Solanum quitoense L)

Abstract

The fruit and vegetable sector faces problems related to poor postharvest handling, which generates high percentages of losses. Lulo (Solanum quitoense), a highly desirable Andean fruit in the national and international market, has a climacteric physiology that accelerates its metabolism and decreases its shelf life; for this reason, the development of edible coatings from biopolymeric materials has been promoted. The objective of the research was to compare the effect of different coating formulations based on polysaccharides (pectin or hydroxypropyl methylcellulose (HPMC)) and protein (gelatin) on weight loss (%), color index and firmness (N) in lulo. The fruits were selected, conditioned and distributed in nine (9) treatments with proportions 75/25 %, 50/50 %, 25/75 % and 100 % of total biopolymers (3 % w/v) and uncoated fruits as control. All were stored for 15 days under ambient conditions (18.84 ± 1.07 °C and 51.33 ± 4.55 % relative humidity (RH)). The results indicated that T2 (50/50 % pectin/gelatin) presented the lowest weight loss (9.654 ± 0.9 %) for the last day of evaluation and was reduced by 16.40 % with respect to the control, preserved color (9.909 ± 0.3) and maintained fruit firmness (26.879 ± 4.0 N). This showed a better synergistic effect between the protein and the polysaccharide on fruit properties, thus becoming a viable and applicable alternative for conservation and its contribution to reducing postharvest losses.