Mechanical properties and antimicrobial efficacy of active wrapping paper for primary packaging of fruits

• Effect of antimicrobial and ethylene scavenging agent on wrapping paper for fruits is reported.
• Sodium permanganate had most evident effect on strength and antimicrobial efficacy of the paper.
• Optimized composition wrapped on peaches, plums slowed physiological changes during storage.
• Use of active wrapping paper shall be useful for extending the marketable period of fruits.

The present study reports the effect of antimicrobial agents (potassium sorbate and potassium metabisulphite) and an ethylene scavenger (sodium permanganate) as coating material on wrapping paper for individual packing of fruits. The effect of these coatings on the paper′s physical strength and antimicrobial efficacy was modeled using regression analysis (R2>79.5%). Optimization of the composition of the coating solution was done such as to obtain maximum strength and antimicrobial efficacy of the paper. The inhibitory effect of sodium permanganate on growth of Candida pelliculosa (58%) was most evident, however it had a weakening effect on the physical strength of paper (tensile strength, percent stretch, tensile energy absorption and stiffness). Potassium sorbate exhibited lesser deleterious effect on the physical strength parameters while decreasing growth of C. pelliculosa and Kloeckera apis (>18.8%). Paper coated with optimized combination of chemicals (degree of desirability: 0.835) was tested for its effect on the physicochemical changes of climacteric fruits like peach and plum during storage at room temperature (32±2 °C). Physiological changes were much less in active wrapped fruits after six days of storage as compared to unwrapped fruits. This was especially notable in case of puncture resistance (85% increase) and total soluble solids (4±1° Brix increase) in control fruits, compared to 64% and 1° Brix increase respectively, in active wrapped fruits. Thus, use of active wrapping paper will be quite useful for extending the marketable period of climacteric fruits thereby enhancing the marketability and profitability of retailer.