L. J. Malcolmson

Sensory stability of canola oil: Present status of shelf life studies

Sensory studies on autoxidation of canola oil, stored under several variations of Schaal Oven test conditions, suggest an induction period of 2–4 d at 60–65°C. Similar induction periods have been observed between canola and sunflower oils, whereas a longer induction period has been found for soybean oil. Canola oil seems to be more stable to storage in light than cottonseed and soybean oils but is less stable than sunflower oil. Storage stability of products fried in canola oil is similar to products fried in soybean oil. Storage stability of canola and cottonseed oils that had been used in the frying of potato chips showed that canola oil was more prone to autoxidation during storage at 40°C. The presence of light aggravated the oxidative effects and was similar for both oils. Advances in our knowledge about the shelf life of canola oil would be strengthened by standardization of Schaal Oven testing conditions and by specifying the testing protocol for photooxidation studies. Methods for training of panelists and for handling and evaluating oils and fried foods require definition. Rating scales used in the evaluation of oils need to be evaluated to ensure that reliable and valid measurements are achieved. Further progress is needed in the identification of chemical indicators that can be used to predict sensory quality of oils.

Characterization of stored regular and low-linolenic canola oils at different levels of consumer acceptance

A ten-member trained sensory panel evaluated regular (RCO) and low-linolenic (LLCO) canola oils that had been stored at 60°C to four levels of consumer acceptance identified in a prior study. These levels were 70, 60, 50, and 40% acceptance for RCO and 80, 70, 60, and 50% acceptance LLCO. Painty odor intensity increased as consumer acceptance decreased. This same trend was found for chemical measurements of peroxide values, total volatiles, total carbonyls, unsaturated carbonyls, and dienals. These chemical indices were significantly correlated with each other, suggesting that they can be used to monitor related changes in oil quality with respect to lipid oxidation. Values for 19 individual volatiles at each consumer acceptance level were also reported. The data collected in this study provide chemical and sensory characterization of stored RCO and LLCO at distinct levels of consumer acceptance.

Development of a gas chromatographic system for trapping and analyzing volatiles from canned tuna

Abstract Profiles of canned tuna volatiles were obtained using a simple and effective isolation system and high resolution gas chromatography. A high correlation between the volatile profile, chemical groups of components identified and sensory panel scores was obtained. Two models based on chemical groups of components were developed to predict decomposition and rancid off-odor. Recovery of over 80% of the volatile components from canned tuna was obtained with a coefficient of variation of 3.2%.

Magnitude Estimation of Infant Foods II. Taste, Texture and Odor of Infant Formulas

Abstract Thirteen infant formulas were evaluated by a trained sensory panel using magnitude estimation. Of the formulas evaluated, five were commercially prepared formulas based on cows milk, four were commercially prepared formulas based on soy isolate and four were home–made formulas prepared using whole and evaporated milk. Five odor (sweet, sour, cereal, hay/beany, evaporated milk), six flavor–by–mouth (sweet, sour, bitter, cereal, hay/beany, evaporated milk) and two textural (mouthcoating, astringency) characteristics were evaluated for each formula. All formulas were perceived to be mouthcoating, astringent, sweet, and have an evaporated milk flavor. As well, all formulas were found to have a slight cereal and evaporated milk odor. The 1 to 2 week whole and evaporated milk formulas and the soy based formulas were found to be extremely sweet and were significantly sweeter than the 5 to 6 month whole and evaporated milk formulas and the commercially prepared cows milk formulas. As expected, the soy based formulas were also found to have a strong hay/beany flavor. The evaporated milk formulas and the commercially prepared cows milk formulas had a strong evaporated milk flavor. Placement of the infant formulas on the basic taste power functions permitted a direct comparison of the intensity of the basic tastes of the formulas to the basic taste stimulant.

Relationship between sensory clarity and turbidity values of apple juice

Abstract The relationship between sensory estimates of clarity and instrumental turbidity values was determined using a series of apple juice turbidity solutions prepared from a stock solution of kaolin and apple juice. Sensory clarity was assessed by eight experienced panelists using the method of magnitude estimation, and instrumental turbidity readings were obtained using a nephelometer. A linear relationship was found where log perceived clarity = −0.54 (log instrumental turbidity) + 1.83. The calculated slope indicates that a large change in turbidity was necessary before the panelists could observe a change in clarity. This equation was used to predict sensory clarity from instrumental turbidity values for commercial apple juice samples.

Magnitude Estimation of Infant Foods III. Taste and Texture of Infant Cereals

Abstract Three dilutions of six infant cereals were evaluated by a trained sensory panel using the method of magnitude estimation. A total of four flavor by mouth characteristics (sweet, bitter, hay/beany, cereal) and five textural characteristics (viscosity, mouthcoating, astringency, pulpiness, chalkiness) were evaluated for each cereal. All cereals were found to be in varying degrees viscous, mouthcoating, astringent and have a slight cereal flavor. All cereals except Sobee were considered to be pulpy. Sobee was perceived as being chalky. Most cereals were also found to be slightly sweet and have a slight hay/beany flavor. The two soy cereals were also found to be slightly bitter and were in general the most complex of cereals evaluated in terms of flavor and texture intensities. Rice was the least complex cereal. Few differences in the sensory properties of rice, barley, oatmeal and mixed cereals were found. Generally, the intensity of a sensory parameter increased with a corresponding increase in the solids content of the cereal. Placement of the infant formula on the basic taste power function permitted a direct comparison of the intensity of the cereal to the basic taste stimulant.