DYNAMIC ELASTIC PROPERTIES AND SENSORY QUALITY OF APPLE FRUIT

A nondestructive resonance technique for measuring the textural qualities of apple fruit was evaluated. The resonance frequency, f, and the mass, m, were measured on each intact fruit, and a factor, f²m, was computed. This resonance factor, f²m, directly reflected the elastic properties of the fruit flesh and correlated significantly with sensory judgements of apple firmness during harvest. The dynamic resonance test is not as reliable an index of sensory firmness as the pressure test, but it has the advantage of being nondestructive.     

冰淇淋的感官评定方法与感官质量控制

介绍冰淇淋的感官评定要素,包括:建立感官实验室、培训感官品评员、选择感官品评方法,并阐述冰淇淋的感官质量控制方法.     

RELATIONSHIP BETWEEN SENSORY EVALUATIONS AND NONDESTRUCTIVE OPTICAL MEASUREMENTS OF APPLE QUALITY1

A nondestructive optical method was studied for estimating the sensory quality of Golden Delicious and York Imperial apples. The coefficients of determination were significant for estimating sweetness of York Imperial, acidity of Golden Delicious and York Imperial, and crispness, hardness, toughness, and juiciness of Golden Delicious apples using optical measurements. The coefficients of determination were weakest with optical data at a single wavelength, intermediate with optical data compensated for fruit size and drift of instrument current, and strongest with multiple wavelength data. These analyses indicate that 30 to 50% of the variation in sensory attributes can be accounted for by factors affecting optical density of the fruit at specific wavelengths.     

SENSORY EVALUATION OF THE TEXTURE OF 49 COMMERCIAL APPLE AND PEAR PUREES

ABSTRACT

The sensory texture of 49 market samples of pear and apple purees were examined by Flash profile and results were treated by Generalized Procustes Analysis. The product set encompassed grocery products, baby foods and drinking snacks. Four main sensory notions were used to describe the texture of this type of products: graininess, viscosity, moisture and grittiness. Pear and apple purees were discriminated by the gritty perception, carried out on the third component. The other three main characteristics were carried out on the first two axes, where six main groups of products were identified. Pear purees were close to baby foods. Thickened baby foods and pear and apple mixtures constituted additional groups. Finally, apple purees were close sensorially, but three groups could be discriminated by grainy and viscous perceptions. The number of products was not an obstacle and the panel managed the task as required.

PRACTICAL APPLICATIONS

Flash profile seems to be a powerful tool to provide a statement of the sensory diversity of a specific market very quickly even when the number of products is quite large.

     

THE SENSE OF SMELL IN FOOD QUALITY AND SENSORY EVALUATION

The sense of smell is the major contributing sensory system in the perception of food aromas and volatile flavors. Illustrations of the importance of olfactory sensations can be found in the literature on product quality defects and in the importance of aroma andflavor characteristics in driving consumer acceptability of foods. Assessing olfactory-mediated characteristics of flavors is challenging, however, for a number of reasons. There are wide individual differences in olfactory acuity, as suggested by the existence of specific anosmias. Panelists are often strongly influenced by the immediate context in which samples are judged. Developing a useful consensual language to describe smells in sensory analyses can also be difficult. In spite of these challenges, the human sense of smell is the ultimate discriminator of food aroma and flavor quality; instrumental analyses are a poor substitute. Even in cases in which chemical components of food flavors have been identified, these must be cross-referenced against human sensitivities in order to estimate their sensory impact.     

PHYSICAL–CHEMICAL AND SENSORY QUALITY EVALUATION OF GARLIC CULTIVARS

ABSTRACT

Physical–chemical quality of 14 garlic cultivars grown in Spain was analyzed, and the cultivars were classified into three types: purple, white and Chinese, in order to show the possible differences among them. The most useful instrumental color parameter to discriminate among the different types of garlic was lightness (L*). The high pH value of the purple‐type cultivar Moraluz, and the high content of d ‐glucose, d ‐fructose and total sugars of the Chinese‐type cultivars were quite remarkable. The consumer judges preferred the color and pungency of the purple‐type cultivar Morasol, while Chino Sprint stood out for its intense garlic odor. Finally, correlations between the physicochemical and the sensory parameters were studied. The red color intensity was correlated with lightness (L*) and with hue (h*); pH was correlated with chroma (C*) and moisture percentage was correlated with sucrose content.

PRACTICAL APPLICATIONS

One of the main objectives of this work was to advise growers on the selection of garlic seed. The data obtained in this work was sent to a regional research and advising agronomic center (Technical Agronomic Institute, provincial council of Albacete), where advice was given to local growers concerning the selection of the most adequate seeds, in terms of physical– chemical properties and consumer preference, plus agronomic performance (data not included in this article). The conclusions reached in this study will make an important contribution to the agronomic characterization of the garlic cultivars grown in Spain.

     

SAFFRON: QUALITY EVALUATION BY SENSORY PROFILE AND GAS CHROMATOGRAPHY

Saffron the valuable stigma from flowers of Crocus sativus L, valued essentially for delicate flavor has specific testing methods for physical, chemical, microscopic parameters, in addition to pigments, and bitter principle but not for flavor. The flavor profile pattern as cob-web diagrams are reported. The dose-response relationship for saffron flavor (due to the principal flavor component, safranal) is established with n = 0.75 for a modified Stevens' equation. Importance of examination of flavor is highlighted for grading in view of new developments in postharvest technology and synthetic safranal entering the market. The GC peak identification of safranal by liquid and headspace GC and GC-MS is demonstrated and confirmed from bioassay at the exit port by sniffing.     

PREDICTING HEDONIC RATINGS OF RAW CARROT TEXTURE BY SENSORY ANALYSIS

A trained panel was used to evaluate degrees of flexibility, hardness, chewiness, and juiciness, while an untrained panel indicated hedonic values for texture on a rating scale. A multiple regression analysis showed that 83% of the variation in the hedonic ratings could be accounted for by sensory scores on flexibility, hardness, and chewiness.     

EVALUATION OF SWEET POTATO CULTIVARS AND HEATING METHODS FOR CONTROL OF MALTOSE PRODUCTION, VISCOSITY AND SENSORY QUALITY

Two varieties of sweet potato were subjected to four cooking temperature‐time combinations. A fifth treatment involved adding maltose syrup. Raw comminuted sweet potato mash and cooked sweet potato puree were evaluated for total solids, alcohol insoluble solids, commonly occurring sugars, viscosity (puree only) and for starch gelatinization temperatures. The uncooked Owairaka Red variety was higher in total solids and in alcohol insoluble solids than the Toka Toka Gold. With the exception of the cooked puree with added maltose, baking at 200C resulted in puree with the highest maltose levels. A very fast cooking procedure tended to result in puree with lower levels of maltose and high viscosity. Sensory studies revealed that the Owairaka Red variety produced puree with more viscous and adhesive mouth feel. It was concluded that cooking alone could not be used to optimize both maltose production and viscosity.     

OBJECTIVE EVALUATION OF CANNED TUNA SENSORY QUALITY

SUMMARY— Commercial and experimental packs of canned tuna were prepared from the 1965, 1966 and 1967 packs. The 1965 samples were used to train an expert panel which identified 8 distinct parameters of quality. Of the 64 objective tests or variations of test procedures, 13 were selected for further study. 1966 analyses revealed that color, flakiness, firmness and fiber could be predicted adequately (R = 0.9 +). The 4 other parameters of scorch, juiciness, odor and taste were also highly significantly correlated, but were predictable less completely (R = 0.8 – 0.9) by 1 or a combination of objective tests. 1967 samples were submitted to a consumer preference panel in addition to measurements by expert panel and objective tests. These results indicated that consumer preference is dependent approximately equally (40%) on appearance and flavor and to a lesser extent (20%) on textural characteristics. Consumer preference could be estimated objectively by determinations of Hunter L and b values, a shear test, percent fiber and PH.     

QUALITY EVALUATION OF MELON CULTIVARS. CORRELATION AMONG PHYSICAL-CHEMICAL AND SENSORY PARAMETERS

Soluble solid content, pH, firmness and color as measured by tristimulus colorimetry of nine cultivars of melon (Cucumis melo L.) were correlated with external appearance, texture and flavor. The Piel de Sapo type cultivars, RQ‐200 and Sancho, were the most appreciated for their external appearance, and MTV, a Rochet type cultivar, was preferred for its texture and flavor. ACL, a Yellow type cultivar, showed the highest pH and soluble solids (SS) content, while the Tendral type cultivars were the firmest. Flavor was positively correlated with pH and SS content, which confirms consumers’ preference for fruits with a high pH and high sugar content. The negative correlation between firmness and texture suggests that consumers prefer tender fruit. The colorimetric parameters served to differentiate three groups of cultivars as regards external color: Yellow type cultivars, Tendral type cultivars and Piel de Sapo and Rochet type cultivars. As regards internal color, none of the parameters clearly discriminated between the types of cultivars considered.     

UV INACTIVATION OF E. COLI O157:H7 IN APPLE CIDER: QUALITY, SENSORY AND SHELF-LIFE ANALYSIS

Increasing concern about food safety following contamination of unpasteurized apple cider with Escherichia coli O157:H7 reinforces the need for using the best technologies in apple cider production. Pasteurization of apple cider with ultraviolet irradiation (UV) is a low‐cost alternative to heat pasteurization for small processing operations. UV treatment efficacy applied to raw unpasteurized apple cider was examined through evaluation of physical parameters, exposure time and treatment dosage. A UV light processing system was used to treat apple cider. The apple cider received a calculated average dosage of 8777 µW‐s/cm ² per pass through the system. UV light (at 254.7 nm) was effective in reducing bacteria‐inoculated apple cider by an average of 2.20 logs per pass. In multiple passes, the 5‐log reduction mandated by the Food and Drug Administration was achieved. Sensory analysis yielded no significant differences between the UV‐treated and control apple ciders. Experiments with UV‐treated apple cider indicated a significant extension of product shelf life through inhibition of yeast and mold growth. For low throughput apple cider processing operations, this technology is a viable cost‐effective alternative.     

PHYSICAL-CHEMICAL AND SENSORY QUALITY EVALUATION OF POTATO VARIETIES (SOLANUM TUBEROSUM L.)

Seven table potato varieties were studied for pH, soluble solids content, moisture, firmness, color, external appearance of raw tubers and flavor and texture of the fried and boiled product. Monalisa was the most appreciated variety regarding external appearance, Bartina was preferred for the flavor of the fried product while Victoria and Desiree were the best for flavor and texture of boiled potatoes. The different scores by variety depending on frying or boiling suggest a specific use for each variety. Soluble solids content, pH, and moisture determinations showed minimal differences between varieties. Firmness was highest in the two varieties with the least moisture (Desiree and Victoria) and lowest in varieties with a high degree of moisture (Bartina and Caesar); fresh potato firmness had a positive correlation with these sensorial parameters when the product was boiled. All colorimetric parameters were useful to discriminate red skin from yellow‐white skin varieties.