The role of packaging on the flavor of fluid milk

Few studies have addressed the effects of package ma-terial in the absence of light on contributions to fluid milk flavor. The objective of this study was to compare the sensory and chemical properties of fluid milk pack-aged in paperboard cartons, low-density polyethylene, high-density polyethylene (HDPE), polyethylene tere-phthalate (PET), linear low-density polyethylene (LL-DPE), and glass. Pasteurized (high temperature short time, 77 degrees C for 25 s) skim and whole milk were filled (280 mL +/- 10 mL) into paperboard cartons, low-densi-ty polyethylene, HDPE, PET, LLDPE, and glass (con-trol). Milks were stored at 4 degrees C in the dark and sampled at d 0, 5, 10, and 15. Descriptive analysis was applied to document sensory profiles at each time point, and volatile compounds were extracted and identified by solid-phase microextraction with gas chromatography mass spectrometry and gas chromatography-olfactom-etry. Tetrad tests with consumers were conducted at d 10. Both skim and whole milks packaged in cartons had noticeable paperboard flavor by d 5 and higher levels of hexanal than skim and whole milks in other package types at d 5. Skim milks packaged in paperboard car-tons and LLDPE had distinct refrigerator/stale flavor compared with milks in the other package types, con-current with increased levels of refrigerator/package-related compounds including styrene, acetophenone and 2-ethyl-1-hexanol. Milks packaged in glass, PET and HDPE were not distinguished by consumers at d 10 post-processing. Package type influences fluid milk flavor, and these effects are greater in skim milk com-pared with whole milk. Paperboard cartons do not pre-serve milk freshness, as well as PET, HDPE, or glass, due to flavor migration and scalping. Glass remains an ideal barrier to preserve fluid milk flavor, but in the absence of light, HDPE and PET provide additional benefits while also maintaining fluid milk flavor.

Automated summary

This study compared the sensory and chemical properties of fluid milk packaged in paperboard cartons, low-density polyethylene, high-density polyethylene, polyethylene terephthalate, linear low-density polyethylene, and glass in the absence of light. The results showed that milk packaged in paperboard cartons had noticeable paperboard flavor by day 5 and higher levels of hexanal compared to other packaging types. Glass, polyethylene terephthalate, and high-density polyethylene packaging were not distinguished by consumers at day 10. Package type influences fluid milk flavor, with greater effects found in skim milk compared to whole milk. Paperboard cartons do not preserve milk freshness as well as other packaging types, due to flavor migration and scalping. Glass remains the best option for preserving fluid milk flavor, but HDPE and PET provide additional benefits in the absence of light.