Measurements of degradation in frying oils based on oil physical properties and volatile and nonvolatile decomposition products were reviewed. Rapid methods by means of test kits were also considered. Factors that affect the analysis of total polar components (TPC) in frying oils were examined. Relationships between TPC, free fatty acid {FFA} content, Food Oil Sensor readings (FOS), color change (hE), oil fry life and fried-food flavor were evaluated. Flavor scores for codfish, fried in fresh and discarded commercial frying oil blends, were dependent upon individuals in the consumer panel (n = 77). Part (n = 29) of the panel preferred the flavor of fresh fat; others (n = 24) didn't; the rest (n = 24) had no preference. FFA, FOS and TPC were analyzed in two soybean oils and in palm olein during a four-day period in which french fries were fried. Flavor score and volatiles of potatoes fried on days 1 and 4 in each oil were also determined. TPC, FFA and FOS significantly increased (P < 0.05} in all oils during the frying period. TPC and FFA were highest in the used palm olein, and flavor of potatoes fried in palm olein on day 1 was less desirable than those fried in the soybean oils. Potatoes fried in day-1 oils had significantly higher concentrations {P < 0.10) of several pyrazines and aldehydes than those fried in day-4 oils.

ABSTRACT. The purpose of this work was to evaluate the use of antioxidants in extending the shelf‐life of mayonnaise constantly exposed to air in which all of the oil ingredient was fish oil. Mayonnaise prepared without antioxidants had a shelf‐life at room temperature of approximately 1 day. Citric acid or sodium citrate and propyl gallate in the oil phase and EDTA and ascorbic acid in the aqueous phase increased the shelf‐life to an average of 49 days at room temperature as judged by sensory evaluation. With refrigeration, the number of days to off‐odor development was increased to 89. With the addition of an oxygen scavenging system of glucose oxidase‐catalase‐glucose, the shelf‐life increased to an average of 132 days. Both oxygen and light were shown to be detrimental to the stability of the product. Considerable variation was observed between batches of menhaden oil, the primary fish oil used in formulating the mayonnaise in these studies.

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A cloned cDNA partial copy of a soybean leghemoglobin mRNA was used to probe genomic DNA of four species of actinorhizal plants. Southern blot hybridization revealed the presence of sequences with homology to the leghemoglobin probe in DNA from Alnus glutinosa, Casuarina glauca, Ceanothus americanus and Elaeagnus pungens. The hybridization patterns of the restriction fragments revealed some fragment size conservation between the DNA of soybean and the DNA of four actinorhizal plants which are taxonomically unrelated to soybean or to each other. The results presented here indicate that globin gene sequences are much more widely distributed in the plant kingdom than has previously been thought. Furthermore, if sequence conservation is actually as high as the restriction fragment patterns suggest, the evolution of the DNA surrounding the globin sequences has been highly constrained.