Previous investigations, iizcluding those of Kertesz and Sondheimer (8), Mackinney and Chichester (13), Meschter (14), and Nebesky et ccl.(15), have established that the red pigment of strawberry products is unstable in heating and storage, and that many factors can affect the rate at which this pigment degrades. I n a recent contribution from this laboratory ( 4 ) , the changes in color and pigment content of strawberry jellies were studied in relation to the amount of heat applied in processing and in storage.Much of the research carried out by the aforementioned investigators dealt with reactions of strawberry pigment in juice and/or partially purified pigment preparations. A notable exception was the investigation of Sondheimer and Kertesz (20 and 21) into the interrelationship of pigment., ascorbic acid, oxygen, and hydrogen peroxide.In the present research, the degradation of the anthocyanin primarily responsible €or the red color of strawberries was studied in pure pigment solutions. The effects of several factors (temperature, time, pH, oxygen, ascorbic acid, 5-hydroxymethyl-2-furaldehyde, and various potential stabilizers) on the rate of the degradation of this pigment were investigated quantitatively. An effort was also made to evaluate results obtained from the pure pigment study in terms of stabilization of the red color of strawberry juice. EXPERIMENTALPreparation of pure strawberry pigment. Chromatographic analysis reveals the presence of two red pigments in strawborry juice (14). One of them is present in much greater quantity than the other, and has been identified as pelargonidin 3-monoglucoside (19). In the early stage of the present investigation, the picration method (19) was used for the preparation of the major pigment. Later, it was found that paper chromatography results in a greater yield of major pigment and at the same time e e p arates the minor pigment, recently identified as eyanidin-3-glucoside by Lukton, Chi- Chester, and Mackinney (I,?), in recoverable quantities. The paper chromatographic technique used consisted of extracting strawberry juice with one-butanol, shaking the butanolic extract with 3 volumes of hexane, and streaking the red lower phase, which results from the prepious step, on Whatman No. 1 paper. Triangular strips of paper (8 in. base x 20 in. height) were used, with the mixture to be resolved applied as a narrow streak 1 inch from the base and parallel t o it. The solvent was a mixture of

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Frozen beef-soy patties, raw or char-broiled, and frozen fried, breaded chicken parts were heated by various methods and vitamin B, and B, retentions determined. Heating methods used were: hot air convection followed by holding hot for 0, %, l%, or 3 hr and infrared, high pressure steam, or microwave followed by hot holding for % hr. Riboflavin retentions in beef patties were above 89%, except when infrared heating was used (80%). Reheated chicken retained 87-93s of riboflavin and there was no significant difference among treatments. Thiamine retention was lowest in chicken parts reheated by convection and held hot for 3 hr (74%). Infrared heating resulted in 81-84% thiamine retention in beef or chicken while other methods retained 86-96s.

The nonenzymatic discoloration of pureed foods (baby foods) has been the subject of many recent investigations. Livingston, Esselen, and Fellers (5) found that storage temperature and headspace oxygen were critical factors in the browning of apple sauce. These results were corroborated by Vilece (8) who carried out quantitative studies of the effect of oxygen and ascorbic acid on eight fruit and vegetable purees.I t was felt that additional information could be obtained by investigating more extensively the browning of one vegetable product. Green bean puree was selected because it was desired to determine the role of chlorophyll or its degradation products in browning. It was possible to remove all the colored constituents from green bean purke, and thus study browning without the masking effect or reactions of the natural pigments. End products of browning from stored green bean puree were isolated.