No abstract

Pasteurization and freezing are processes used in human milk banks that can affect some of the nutritional and biological properties of human milk. The aim of this study was to evaluate impact of the processing steps adopted by human milk banks on the contents of total phenolic compounds and antioxidant capacity in vitro. Experimental study was realized, in which 40 mL human milk were collected from 8 mothers registered at the Human Milk Bank of Ouro Preto, state of Minas Gerais. Samples were homogenized to form the pool. Human milk was divided into four portions that characterized the treatments: 1) immediately after milking; 2) pasteurization soon after the milking; 3) 7 days after freezing at -8.5 (± 2.8°C) and pasteurized; 4) 14 days after freezing at -8.5 (± 2.8°C) and pasteurized. The content of total phenolic compounds was determined, and the antioxidant capacity was assessed using the 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl free radicals scavenging. The results were expressed as mean and standard deviation of six replications. There was a positive correlation between the evaluated methods and reduction in total phenolic content and total antioxidant capacity with slow pasteurization and according to freezing time. There was a negative effect of pasteurization and freezing on the total phenolic content and total antioxidant capacity, and the most significant reduction was observed within the first 7 days of storage.

This study aimed to evaluate the effect of thermosonication of human milk (HM) followed by frozen storage on its lipid stability, antioxidant activity, and tocopherol content. The treatments investigated in this study corresponded to a factorial structure with additional treatment (control), having processing method and storage time as factors. The additional treatment corresponds to raw milk, with 0 days of storage. The experimental design was the one randomly randomized with three replications. Essential fatty acids and antioxidant activity were conserved by the ferric reducing antioxidant power method but decreased by the 2,2‐diphenyl‐1‐picrylhydrazyl method (9%) in both pasteurized and thermosonicated samples. Only tocopherols showed greater degradation with thermosonication. In freezing, regardless of processing, the same behavior was observed for the analyzed parameters, with a reduction in antioxidant activity and tocopherol isoforms. Hexanal increased during storage for up to 30 days (0.87 μL/mL of HM) regardless of processing. Thermosonication of HM proved to be a method similar to slow pasteurization in the studied parameters. It is suggested that further studies should be conducted on the use of ultrasound as an alternative processing technique to the conventional processes adopted by the Human Milk Bank. Practical Applications Thermosonication proved to be a method similar to pasteurization in the studied parameters. This study is extremely relevant to assist in the determination of new processing techniques to obtain donated HM with better nutritional quality. It is suggested that further studies should be conducted on the use of ultrasound as an alternative processing technique to the conventional processes adopted by the Human Milk Bank.