Avaliação do efeito do processamento térmico na composição química da água de coco por GC-MS, LC-MS e NMR

Abstract

Green coconut water is a refreshing beverage that is consumed not only by its sensory qualities but also by its nutritional and therapeutic properties. Its composition rich in sugars and minerals becomes a perishable product, subject to microbiological contaminations and biochemical changes during the extraction and filling of the liquid. The increase in the productive scale of the product stimulates the development of processes that increase its shelf life, minimizing the sensorial and nutritional losses. However, industrial processing and / or prolonged storage of the coconut water can result in the development of a pink coloration adversely impacting its commercial value. Thus, NMR, GC-MS and UPLC-HRMS coupled to chemometrics were applied to understand variations in the chemical composition of fresh (control) and thermally processed coconut water. The water was extracted from the coconuts dwarf variety and green cultivar in the maturation stage between 6 and 7 months. Two samples were analyzed: one control and one sample thermally processed by UHT sterilization at 110ºC for 8s. Samples processed presented pink color under storage. According to chemometrics, procyanidin A-type dimer and trimer, palmitic acid, stearic acid, sucrose, α-glucose, β-glucose, fructose, ethanol, valine, acetic, malic and lactic acids and six other unknown compounds were responsible for the differences observed between treatments. These compounds may be responsible for the pink color development after processing and storage of coconut water. Future isolations with the structural elucidation of the 520nm absorbing compounds and the understanding of the mechanisms action involved in color formation will clarify this problem found in processed coconut water