The effects of different thawing methods on the nutritional properties in human milk

Article type: Research Article

Authors: Chan, J.T. | Gill, G. | Chan, G.M.

Affiliations: University of Utah School of Medicine, Salt Lake City, UT, USA | Department of Pediatrics, Division of Neonatology, University of Utah, Salt Lake City, UT, USA

Note: [] Corresponding author: Gary M. Chan, 295 Chipeta Way RM 2N106, Salt Lake City, UT 84108, USA. Tel.: +1 801 587 7508; Fax: +1 801 585 7395; E-mail: [email protected]

Abstract: Objective: To compare the effects of four thawing methods on the fat concentration, free fatty acid concentration, total antioxidant capacity, and epidermal growth factor concentration of frozen human milk. Study design: Milk samples were obtained from 16 lactating mothers who delivered prematurely. Milk samples were divided into aliquots and frozen at −20°C. Aliquots were thawed at 4°C (refrigerator), 20°C (room temperature), 50°C (hot water) or microwaved. After thawing, the aliquots were analyzed for fat, free fatty acid concentration, total antioxidant capacity, and epidermal growth factor concentration. Results: The mean fat concentration ( ± SD) was 6.0 ± 1.8 (4°C), 5.9 ± 2.3 (20°C), 4.9 ± 1.8 (50°C), and 4.1 ± 1.8% (microwave), P < 0.001. The free fatty acid concentration was 4.0 ± 1.1 (4°C), 3.6 ± 1.4 (20°C), 2.9 ± 1.5 (50°C), and 2.4 ± 1.4 nmol/μl (microwave), P < 0.001. The total antioxidant capacity was 8.8 ± 1.2 (4°C), 8.2 ± 1.2 (20°C), 7.9 ± 1.5 (50°C), and 7.1 ± 1.1 nmol/μl (microwave), P < 0.001. No statistically significant change in epidermal growth factor concentration was noted. Conclusions: Thawing at 4°C and 20°C had the least effects with microwaving having the most effects on human milk's fat concentration, free fatty acid concentration, and total antioxidant capacity. Epidermal growth factor concentration was not affected by the thawing methods.

Keywords: Antioxidants, child nutritional sciences, epidermal growth factor, fatty acids, feedings, freezing, hot temperature, humans, infant, lactation, lipids, newborn, premature, microwaves, milk, refrigeration, temperature

DOI: 10.3233/NPM-2011-51211

Journal: Journal of Neonatal-Perinatal Medicine, vol. 4, no. 4, pp. 341-346, 2011