Effect of Antioxidant (α-Tocopherol and Ascorbic Acid) Fortification on Light-Induced Flavor of Milk

• Published in: Journal of dairy science 2005-03, Vol.88 (3), p.872-880
• Main Authors: van Aardt, M, Duncan, S. E, Marcy, J. E, Long, T. E, O'Keefe, S. F, Nielsen-Sims, S. R
• Format: Article
• Language: English
• Subjects: alpha-Tocopherol - administration & dosage; alpha-Tocopherol - pharmacology; Animal productions; Animals; antioxidant; antioxidant activity; Antioxidants - administration & dosage; Antioxidants - pharmacology; Ascorbic Acid - administration & dosage; Ascorbic Acid - pharmacology; Biological and medical sciences; Chromatography, Gas; Dose-Response Relationship, Drug; food fortification; Food Handling - methods; Food industries; Food Technology; Food, Fortified; Fundamental and applied biological sciences. Psychology; Kinetics; Light - adverse effects; light-induced flavor; lipid oxidation; lipid peroxidation; milk; Milk - chemistry; Milk and cheese industries. Ice creams; milk flavor; Oxidation-Reduction; Taste - drug effects; Taste - radiation effects; Terrestrial animal productions; Thiobarbituric Acid Reactive Substances - analysis; Vertebrates
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(05)72753-3

The effectiveness of added antioxidants against oxidation off-flavor development in light-exposed milk was evaluated using sensory and chemical analysis. Sensory testing for similarity showed no perceivable difference between control milk and milk with added (1) 0.05% α-tocopherol (TOC) and (2) 0.025% α-tocopherol and 0.025% ascorbic acid (TOC/ASC), but did demonstrate a perceivable difference when adding (3) 0.05% ascorbic acid (ASC) alone. Subsequently, sensory testing for difference showed a significant difference in oxidation off-flavor between light-exposed control milk and light-exposed milk with added TOC/ASC, whereas milk fortified with TOC was not different from control. Gas chromatography-olfactometry showed that more aroma-active flavor compounds were observed in light-exposed milk treated with TOC and TOC/ASC than light-exposed milk with no added antioxidants. The thiobarbituric acid reactive substances (TBARS) test verified chemically the extent of oxidation in control and antioxidant-treated milk samples. Milk that was exposed to light for 10h showed a significantly higher TBARS value (0.92±0.09 mg/kg) than milk that was protected from light (0.59±0.184 mg/kg), or milk that was treated with TOC/ASC (0.26±0.092 mg/kg). Direct addition of low levels of antioxidants (TOC/ASC) to milk protected its flavor over 10h of light exposed storage.