Effect of high intensity pulsed electric fields and heat treatments on vitamins of milk

Abstract

S. The effects of high intensity pulsed electric field (HIPEF) treatments at room or moderate temperature on water-soluble (thiamine, riboflavin, ascorbic acid) and fat-soluble vitamins (cholecalciferol and tocopherol) were evaluated and compared with conventional thermal treatments. Vitamin retention was determined in two different substrates, milk and simulated skim milk ultrafiltrate (SMUF). Samples were subjected to HIPEF treatments of up to 400 µs at field strengths from 18n3 to 27n1 kV\cm and to heat treatments of up to 60 min at temperatures from 50 to 90 mC. No changes in vitamin content were observed after HIPEF or thermal treatments except for ascorbic acid. Milk retained more ascorbic acid after a 400 µstreatment at 22n6 kV\cm (93n4 %) than after low (63 mC-30 min ; 49n7 % retained) or high (75 mC-15 s ; 86n7 % retained) heat pasteurisation treatments. Retention of ascorbic acid fitted a first-order kinetic model for both HIPEF and thermal processes. First-order constant values varied from 1n8i10 −% to 1n27i10 −$ µs −" for the HIPEF treatments (18n3-27n1 kV\cm) and, for thermal processing ranged from 5i10 −$ to 8i10 −# min −" (50-90 mC). No significant differences were found between the results obtained after applying HIPEF treatments at room or moderate temperature. However, results depended on the treatment media. A beneficial effect of natural skim milk components, mainly proteins, was observed on the preservation of ascorbic acid, since skim milk retained more ascorbic acid than SMUF after HIPEF treatments.

Ascorbic acid in orange juice–milk beverage treated by high intensity pulsed electric fields and its stability during storage

“…Several authors have studied the evolution of ascorbic acid in citrus juices or milk after PEF or heat treatment (Bendicho, Espachs, Arántegui, & Martín, 2002;Polydera, Stoforos, & Taoukis, 2003;Torregrosa, Esteve, Frígola, & Cortés, 2006;Yeom, Streaker, Zhang, & Min, 2000), however, no similar studies have been found in more complex matrices such as orange juice-milk beverages. Therefore, the objective of the present work was to study the ascorbic acid degradation in a PEF-treated orange juice-milk beverage.…”

Use of nisin and other bacteriocins for preservation of dairy products

“…As a result, research and development of new products is leading to the reduction or even displacement of heat treatments and traditional preservatives by treatments capable of assuring the sensory and nutritional properties of the product without reducing food safety. Non-thermal preservation methods are thus of growing interest as alternative treatments, especially highintensity pulsed electric fields (HIPEF), high pressure (HP) and the addition of natural antimicrobial substances (Bendicho, Espachs, Ara´ntegui, & Martı´n, 2002).…”

The FAST index – A highly sensitive indicator of the heat impact on infant formula model

“…The initial vitamin C concentration was 103.4 mg/l in the IF preparation. Vitamin C degradation complied with first-order kinetics as expected (Bendicho, Espanchs, Arantegui, & Martin, 2002;Bihel & Birlouez-Aragon, 1998;Burdurlu, Koca, & Karadeniz, 2006;Esteve et al, 1998;Manso, Oliveira, Oliveira, & Frias, 2001) and the first-order rates could be calculated from the slope of the Ln representation. However, above 100°C, the degradation was so fast that very low concentrations, at the limit of the method quantification level, were reached rapidly.…”