Salicylic acid, cinnamaldehyde, and thymol incorporated into cassava starch coatings for mango preservation

Abstract

Mango is a fruit consumed all over the world. There are some methods used during storage such as modified atmosphere, hot steam, irradiation, wax coating, and immersion in hot water to extend mango shelf life. However, heat treatment accelerates maturation and reduces organoleptic quality. Edible coatings are also used to extend the shelf life of food. Edible coatings are layers made of proteins, polysaccharides, lipids, antimicrobial components, antioxidants, or a mixture of them. Additives with antimicrobial, antioxidant, or other properties, are added to coatings to improve their functionality. Coatings improve food quality by slowing down unwanted changes and extending shelf life. Knowing that starch is not the best material for preparing edible coatings, in the present work, it was modified by adding salicylic acid or a cinnamaldehyde-thymol mixture to the cassava starch coating-forming solution. Cassava starch or chitosan coatings were applied to Tommy Atkins mangoes. Total soluble solids, titratable acidity, weight loss, and instrumental texture (firmness) were determined over four weeks of storage at 12 °C and 90% of relative humidity. Mangoes coated with cassava starch containing salicylic acid (SSA) had the highest weight loss, while fruits coated with starch-cinnamaldehyde-thymol (SCT) had the lowest weight loss during the whole storage time. The titratable acidity showed a decrease throughout the four weeks of storage. However, in the third week of storage, mangoes coated with chitosan, SSA, and SCT samples ripened more slowly, as indicated by higher acidity than uncoated samples. The SSA and chitosan-coated mangoes showed statistically similar penetration forces that were also higher than the SCT and uncoated samples. Cinnamaldehyde-thymol improved the hydrophobic characteristics of the starch coatings and therefore, it reduced the weight loss of mango during storage.