Effectiveness of poly(ethylene terephthalate) and high-density polyethylene in protection of milk flavor.
The development of certain off-flavors in whole milk (3.25% milk fat) as related to packaging material [glass, high-density polyethylene (HDPE), amber poly(ethylene terephthalate) (PETE), clear PETE, and clear PETE-UV] were evaluated after exposure to fluorescent light (1100 to 1300 lx) for 18 d at 4 degrees C. Control samples packaged and stored under identical conditions were wrapped in foil to prevent light exposure. Selected flavor compounds in milk were measured analytically on d 0, 7, 14, and 18 of storage, while intensities of "oxidation," "acetaldehyde," and "lacks freshness" off-flavors were determined by sensory analysis at the same intervals. In light-exposed samples, oxidation off-flavor was significantly lower when packaged in amber PETE versus other containers. Milk packaged in HDPE containers showed a significantly higher level of oxidation off-flavor than milk packaged in PETE-UV containers but not higher than clear PETE or glass containers. No significant difference in acetaldehyde off-flavor was found between package material treatments (exposed or protected). Acetaldehyde concentration never exceeded flavor threshold levels, regardless of packaging material. Amber and PETE-UV materials proved to be a competitive packaging choice for milk in preserving fresh milk flavor.
van Aardt
M
M
Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA. mvanaard@vt.edu
Duncan
S E
SE
Marcy
J E
JE
Long
T E
TE
Hackney
C R
CR
D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005453:Fluorescence; D018857:Food Packaging / Q000295:instrumentation* / Q000379:methods; D005519:Food Preservation; D005524:Food Technology; D006801:Humans; D008027:Light; D008892:Milk / Q000737:chemistry / Q000528:radiation effects* / Q000592:standards; D010084:Oxidation-Reduction; D020959:Polyethylene; D011093:Polyethylene Terephthalates; D013649:Taste; D013652:Taste Threshold; D013997:Time Factors
D011093:Polyethylene Terephthalates; D020959:Polyethylene