Fruit quality retention and shelf-life extension of papaya through organic coating

Abstract

Papaya (Carica papaya L.) is a climacteric fruit which lose quality and shelf life quickly due to physiological decay and microbial infection after harvest. The study was conducted to evaluate newly applied clybio formulation (0.2 %) along with the existing effective concentration of chitosan (1 %), aloevera gel (50 %), seaweed extract (1 %) and uncoated papaya (control) fruits on post-harvest physicochemical properties and disease incidence when stored at 25 ± 1 °C and 85-90 % relative humidity. Quality parameters were available up to 12 days of storage (DAS) for chitosan and clybio treated papaya where it was 9 DAS for aloevera gel and seaweed treated papaya and 6 DAS for control papaya. Before decay of all the coated papaya at 9 DAS, chitosan (1 %) performed superior in retaining maximum reducing sugar (0.77 %, 1.41 % and 3.85 % more than aloevera, seaweed and clybio application, respectively), β-carotene (10.94 %, 12.5 % and 9.89 % greater than aloevera, seaweed and clybio coatings, respectively), total flavonoids content (18.36 %, 29.81 % and 25.29 % better than aloevera, seaweed and clybio treatments, respectively), total antioxidant activity (21.85 %, 68.2 % and 47.91 % than noted in aloevera, seaweed and clybio formulations, respectively) and potassium content (3.14 % and 9.32 % than aloevera and clybio treatments, respectively). In addition, clybio gave better results over chitosan up to completion of shelf life (12 DAS) such as retention of ascorbic acid (6.21 %), non-reducing sugar (13.48 %), magnesium content (8.31 %) and disease incidence (20 %). Thus, besides preserving nutraceutical property, chitosan and clybio coated papaya remained edible for further 6 days compared to control, and 3 days over aloevera gel and seaweed extract treatment. These findings suggest the use of chitosan and clybio formulation for preserving quality parameters and extending the storage life of papaya.

Keywords: Carica papaya L.; Climacteric fruit; Disease incidence; Postharvest treatment; Quality parameters; Storage life.

Graphical abstract

Fig. 1

Fish-Bone diagram depicting the various variables that influence the treatment selection.

Fig. 2

Changes in ascorbic acid and β-Carotene of papaya during storage at room temperature.

Fig. 3

Changes in total phenol content (TPC) of papaya during storage at room temperature.

Fig. 4

Changes in total flavonoid content (TFC) of papaya during storage at room temperature.

Fig. 5

Changes in DPPH radical scavenging activity of papaya during storage at room temperature.

Fig. 6

Visual and microscopic view of anthracnose damage and pathogen.

Fig. 7

Effect of various organic coatings on shelf life of papaya at room temperature.

Fig. 8

Effect of coatings on physical appearance during storage.

Fig. 9

Correlation matrix in between and among changing pattern of parameters studied for papaya quality storage at 9 DAS. Positive correlations are displayed in blue and negative correlations in red color. DI, disease incidence; TFC, total flavonoid content; NRS, non-reducing sugar; TSS, total soluble solid; AOS, Total antioxidants activity; TS, total sugar; AA, ascorbic acid; RS, reducing sugar; TPC, total phenol content.

Fig. 10

Heatmap representation of changeable parameters at 9 DAS of both treated and untreated papaya with a hierarchical clustering is shown. Blue and red colors represent reduced and increased rate of changes. DI, disease incidence; TFC, total flavonoid content; NRS, non-reducing sugar; TSS, total soluble solid; AOS, Total antioxidants activity; TS, total sugar; AA, ascorbic acid; RS, reducing sugar; TPC, total phenol content.

Fig. 11

Principal component analysis (PCA) of the changeable parameters studied for postharvest storage of papaya. (A) PCA of the variables showing their major contribution. (B) PCA–biplot analysis representing the performance of changeable parameters effected by different treatments. T₁, T₂, T₃, T₄ and T₅ indicate control, aloevera gel, seaweed extract, chitosan and clybio formulation, respectively. DI, disease incidence; TFC, total flavonoid content; NRS, non-reducing sugar; TSS, total soluble solid; AOS, Total antioxidants activity; TS, total sugar; AA, ascorbic acid; RS, reducing sugar; TPC, total phenol content.