Revestimento de mamão Havaí (Carica papaya L.) desenvolvido com filme de coproduto da indústria pesqueira adicionado de extrato de semente de pitomba (Talisia esculenta radlk)

Abstract

The food industry suffers high losses with fruits and vegetables throughout the entire production chain, which encourages it to search alternatives such as the development of films to coat food and prolong its shelf life. The objective of this work was to seek an optimized coating capable of prolonging the shelf life of papaya that is affected by post-harvest diseases caused by Collectotrichum gloeosporioides and Fusarium spp. The coatings / films can be obtained from gelatine from fishing industry’s co-products, such as Nile’s tilapia’s (Oreochromis niloticus) skin of the whose processing results in more than half of the animals' weight as co-products. For the conversion of hides into gelatins, it was required to perform permutations between three reagents in the following recommendations: butanol 15%, hydrochloric acid 0.8% and acetic acid 0.8%. Analyzes of the different solutions were carried out in order to obtain the optimized base, that is, with high gel strength and low lipid concentration. The gelatin chosen for making the film was a number 9 made with 25% butanol and 37.5% acetic acid (0.8%) and hydrochloric acid (0.8%) which contained a content of 7.76% humidity, 1.42% ash, 84.93% protein, 0.43% lipids, 2.94 pH and 872.20 bloom of gel strength, generating a yield of approximately 13%. After preparing the film with this optimized gelatin and surfactants (Tween 80 and sodium dodecyl sulfate (SDS)), the mechanical and barrier properties were investigated. Tensile strength, Young's modulus and elongation values were found from 3.49 to 38.78 MPa; 1.97 to 14.16 MPa; and 16.40 to 120.49%, respectively. As for the water vapor permeability barrier property, a low value range of 5.90 to 10.12 g.mm.h-1.m2.kPa-1 was found. The thickness varied according to the addition of surfactant, ranging from 0.10 to 0.25 mm. The treatment with the lowest concentration of surfactant (40%) was the most efficient, as it had the best barrier properties and was the least thick, which classifies it as a good option for coating food. This film was then applied to systems with different relative humidity in order to obtain an adsorption isotherm and the Kühn model allowed the best adjustment to the experimental data, considering all the statistical parameters and the random (randomized) distribution of the residues simultaneously. The effect of the application of this film was investigated, through physical-chemical analyzes during the ripening, when different concentrations of pitomba’s extract were used. It was found that the parameters L, C and h are capable of expressing color changes during ripening in both the skin and the pulp. The content of total soluble solids is closely related to the ripening of the fruit and was found in the range of 8.77 to 11.95º Brix where only one formulation wasn’t able to meet the minimum amount of ºBrix of ripe papayas, suitable for export. The lycopene content was 12.28 to 25.79 μg lycopene / g of papaya for the analyzes on the final day. The loss of mass in all cases was less than 10%, but the most significant losses were related to the presence of post-harvest diseases. As a conclusion, it was observed that concentrations of pitomba extract from 10% would be able to reduce the post-harvest diseases present and delay the ripening of the papaya, being attractive to the foreign market.