AJ3STRACTFrozen orange juice concentrate (63.8" Brix) was reconstituted with water to single strength juice and supplemented with a commercial citrus pectinesterase (PE) to give an activity of 1.5 PE units/ml juice. Reconstituted juice and freshly squeezed single strength orange juice -_ were treated with a cation exchange resin. Resin treatment decreased the OH of the iuice from 3.75 to 2.0 and comuletelv inactivated PE. PE &as also &activated following acidification' of the juice to pH 2.0 with concentrated hydrochloric acid. Very little cloud loss occurred in refrigerated (4°C) juice at pH 2.0 for approximately 12 wk; however, a loss (> 95%) of ascorbic acid resulted. Only microorganisms died-off rapidly (> 99.9%) in juices adjusted to pH 2.0 using ion exchange resin, but not in juices lowered to pH 2.0 with HCl.

Sesquiterpeneless essential oils were prepared by extracting commercial cold-pressed Valencia orange oils with aqueous ethyl alcohol.. Two levels of alcohol, 60 and 70%, were used to extract the oils in three different .oil-solvent ratios. Quantitative and qvalitative composition of the individual components of the extracts was established by gas chromatography and mass spectrometry and confirmed using standard compounds. The ratio I:3 oil:solvent resulted in sesquiterpeneless oils with the lowest terpene content. However, this ratio also gave the lowest oil recoveries. The highest oil recoveries were obtained with the ratio 1: 15, but d-limonene was present in high concentration. The process produced a terpeneless and sesquiterpeneless orange oil which should have unique flavor applications.

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Nonvolatile products generated from reactions of graded molar ratios of aqueous chlorine or chlorine dioxide with L‐tryptophan (1:1, 3:1 and 7:1) were shown to be direct‐acting mutagens to Salmonella typhimurium TA100 and TA98. Increasing the ratio of disinfectant relative to amino acid led to increased mutagenic activity, with mutagenicity highest at the 7:1 molar ratio. Several fluorescent bands obtained after thin layer chromatographic fractionation of the reaction mixtures were shown to be more mutagenic than the reaction mixtures. GC/MS analysis of the compounds in a highly mutagenic fraction of the aqueous chlorine reaction products identified 1,1,3‐trichloropro‐panonc, 1,1,3,3‐tetrachloropropanone and dichloroquinoline.

Reactions of tryptophan, N-methyltryptophan and 3-indolelactic acid with aqueous chlorine or chlorine dioxide (CIO,) in O.lM potassium phosphate buffer, pH 6.0, were investigated to determine any structural relationships with regards to kinetics and mutagenicity. The rcaction with CIOz followed pseudo-first order kinetics, with the halflife of the respective compounds being 36, 22, and 8 milliseconds. The formation of a dark precipitate in the reaction of tryptophan with HOC1 precluded any kinetic comparison. The reaction products of tryptophan with hypochlorous acid (HOCI) or CR& were mutagenic to Solmoneffu fyphimurium TA98 and TAIOO; while those of N-mcthyltryptophan with HOCI and CIOz were mom mutagenic toward TA98. Higher recoveries of the reaction products were achieved by passing the acidified (pH 2.5) mixture through an XAD-g/XAD-2 resin column.