Mixtures of seven characteristic flavor solutes commonly found in orange juice were studied for their interaction with low-density polyethylene (LDPE) from aqueous solutions at 20 "C. Precautions were taken t o avoid thermal and chemical degradation of the flavor solutes and degradation components were not found by HPLC analysis. Hydrocarbon monoterpenes showed 3 0 4 0 % sorption by the LDPE over a 25-day period. Oxygenated monoterpenes showed ca. 10% sorption in the same time period. Further study of one of the hydrocarbon terpenes (d-limonene) showed both adsorption (surface attraction) and absorption (matrix dissolution), while its analogous oxygenated terpene (Ccarvone) displayed predominantly adsorption. These findings are useful for deciding proper compensations for changes in flavor profiles in packaged orange juices in contact with LDPE. They also illustrate the importance of learning the nature of polymer-flavour interactions between foods and packaging materials.

No abstract

The hydrolysis of [14C]‐labelled tobacco starch by Rhizopus niveus glucoamylase was investigated using thin‐layer and gel filtration chromatography. Hydrolysis was characterized by a period of rapid [14C]‐glucose release, representing 15–30% of the total radioactivity, followed by a prolonged period of slow [14C]‐glucose release. Pullulanase enhanced [14C]‐glucose release, suggesting the presence of α‐(1→6) branch points. Thin‐layer chromatography was used as a rapid screening method for detecting glucoamylase activity in fractions eluted from a DEAE column of a Thermomyces lanuginosus culture filtrate, and gave results comparable to a coupled enzymatic method. [14C]‐Labelled starch from Canna leaf was less susceptible to amylolytic digestion than [14C]‐labelled tobacco starch.