Cobertura para ovos à base de fécula de mandioca e extrato de alho (Allium sativum L.)

Abstract

Egg quality tends to decrease after laying, especially due to gas exchange that occurs through the shell. Another factor that affects the quality of eggs is the proliferation of microorganisms on their surface, such as mold. Cassava starch and garlic extract-based coatings can contribute to controlling microbial growth and increasing the shelf life of this food. In this context, the objective was to develop coatings for eggs based on cassava starch, added with garlic extracts (aqueous or ethanolic) and evaluate their effects on the physical-chemical and microbiological quality of white eggs, during storage at 28ºC for 63 days. Initially, garlic extracts were obtained by homogenizing garlic bulbs with diluents (distilled water or 70% ethyl alcohol) and determining their minimum inhibitory concentrations. The best results were considered to prepare the coatings to be tested. In the evaluation, a completely randomized design was adopted with three treatments, which were: OSR (uncoated egg); OAA (egg coated with cassava starch, glycerol and aqueous garlic extract) and OEA (egg coated with cassava starch, glycerol and ethanolic garlic extract). Throughout the study, the following analyzes were carried out: on the coating (water vapor permeability), on the egg shell (contact angle, scanning electron microscopy, shell color), on the egg (weight loss, yolk percentage, albumen and shell, pH of the yolk and white, specific gravity, yolk index and Haugh unit) and mold count. When compared to control eggs, the coatings presented hydrophilic characteristics and lower luminosity. The coating based on cassava starch and aqueous extract of garlic presented better results for Haugh unit and yolk index, while the coating based on cassava starch and ethanolic extract of garlic presented better results for the percentages of peel, yolk, albumen and was the one that best inhibited the growth of mold. In view of the above, it appears that coatings can contribute to maintaining the quality of commercial white eggs and increasing the product's shelf life, however the use of coatings containing cassava starch and ethanolic garlic extract was the most efficient in controlling mold, the main problem in commercial eggs.