Effect of antioxidant (alpha-tocopherol and ascorbic acid) fortification on light-induced flavor of milk.
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% alpha-tocopherol (TOC) and (2) 0.025% alpha-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 10 h 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 10 h of light exposed storage.
van Aardt
M
M
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Duncan
S E
SE
Marcy
J E
JE
Long
T E
TE
O'Keefe
S F
SF
Nielsen-Sims
S R
SR
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology; D002849:Chromatography, Gas; D004305:Dose-Response Relationship, Drug; D005511:Food Handling / Q000379:methods; D005524:Food Technology; D005527:Food, Fortified; D007700:Kinetics; D008027:Light / Q000009:adverse effects*; D008892:Milk / Q000737:chemistry*; D010084:Oxidation-Reduction; D013649:Taste / Q000187:drug effects / Q000528:radiation effects; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D024502:alpha-Tocopherol / Q000008:administration & dosage / Q000494:pharmacology
D000975:Antioxidants; D017392:Thiobarbituric Acid Reactive Substances; D024502:alpha-Tocopherol; D001205:Ascorbic Acid