EFFECT OF STORAGE CONDITIONS ON THE SENSORY QUALITY OF GROUND ARABICA COFFEE

The objective of this study was to determine how long ground coffee beans could be stored at room and freezing temperatures before sensory changes could be detected, and to identify specific attribute changes associated with this storage. Ground beans were stored for 0 (fresh), 1, 2 and 3 weeks at room and freezing temperatures. Coffee was prepared from each of these treatments and difference testing was performed. Paired comparison tests were conducted on the fresh, 1‐ and 2‐week‐stored coffee grounds to examine the attributes of coffee aroma, flavor, bitterness and overall preference. At room temperature storage, results indicated significant (P < 0.05) differences in the coffee prepared from fresh versus the 2‐week‐stored ground beans. Coffee made from freshly ground beans had a stronger coffee aroma, less bitterness and was more preferred compared with the beans stored for 1 or 2 weeks (P < 0.05). At freezer storage, differences were detected between coffee prepared from coffee grounds stored for 1 or 2 weeks. Coffee prepared from grounds stored for 2 weeks had a stronger coffee aroma and was more bitter compared with the other storage times (P < 0.05).     

INFLUENCE OF OPERATING CONDITIONS ON SENSORY QUALITY OF MINIMALLY PROCESSED OSMOTICALLY DEHYDRATED GUAVA

Abstract The influence of solution temperature (T), process time (t) and pressure regimen (P) on the sensory quality of minimally processed, osmotically dehydrated guava was analyzed. The study encompassed these values of each independent variable: T-30, 40 and 50C; t-60, 120 and 180 min, and P-atmospheric pressure, pulsed vacuum (5 min under vacuum, then atmospheric pressure) and continuous vacuum. The product was sensorially evaluated for color, flavor and firmness. Results were processed by means of the Design Expert version 5 software. Temperature, time and pressure regimen were shown to significantly influence the product's flavor. No effect of the factors on the fruit's color and firmness could be demonstrated. At the cellular level the tissues of guava treated at 40C for 60 min under pulsed vacuum are not significantly altered.     

MULTIVARIATE QUALITY CONTROL WITH APPLICATIONS TO SENSORY DATA

Sensory perceptions of consumer products are generally multivariate. Quality assurance of these products depends on methods that account for multidimensionality. In this paper it is shown how to set multivariate specifications and to use them to establish control charts and acceptance sampling plans for sensory measures of food and beverage products. OC curves describing the operating characteristics of the control charts and the sampling plans are given.     

EARLY DETECTION OF CLOSTRIDIUM PERFRINGENS ENTEROTOXIN AND ITS RELATIONSHIP TO SENSORY QUALITY OF COOKED CHICKEN

Growth, sporulation, and enterotoxin formation by Clostridium perfringens NCTC 8239 were determined in chicken thigh meat incubated at 45°C for 1.5 h and 37°C for up to 12.5 h. With an inoculum of 10⁶ vegetative cells per g, the cell counts reached mean log ₁₀ 7.32/g after 6 h of incubation and remained in that range through 14 h. Heat-resistant spores (log₁₀ 2.48/g) were first detected at 4 h, and the number increased to log₁₀ 5.19/g at 14 h. Enterotoxin (0.19 μg/g) was first detected after 2 h of incubation (1.5 h at 45°C and 0.5 h at 37°C) in the absence of detectable sporulation, and the enterotoxin concentration increased to 0.76 μg/g after 14 h. Significant differences (p < 0.01) in the odor, color, and texture scores for inoculated versus uninoculated cooked chicken following 2 h incubation correlated with the production of enterotoxin and suggested that these parameters could be used as indices of chicken spoilage by C. perfringens.     

MODIFICATION OF CONDITIONS AT THE WHOLESALE WAREHOUSE TO IMPROVE QUALITY OF FRESH-MARKET TOMATOES

Previous studies suggested that modification of storage temperatures at the wholesale warehouse could sufficiently retard ripening to permit harvest of fresh-market tomatoes at a later maturity, thus allowing for greater flavor development on the vine. Tomatoes (cvs ‘Celebrity’ and ‘Sunny’) were harvested either at the breaker or pink stages of maturity. Simulated wholesale storage was conducted by holding breaker fruit for 3 days at 12°C or 21°C and pink fruit for 3 days at 5°C or 37°C. Short-term low- and high-temperature storage of pink tomatoes delayed ripening sufficiently to maintain acceptable color and firmness during retail and consumer storage at 21°C for 7 days. Flavor characteristics of tomatoes harvested at the pink stage of maturity were not significantly superior to those of fruit harvested at the breaker stage. Thus, although ripening can be delayed in pink tomatoes during postharvest handling, delaying harvest from the breaker to the pink stage does not offer the flavor advantage to warrant a change in the handling system.     

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.     

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.     

APPLICATION OF SENSORY,NUTRACEUTICAL AND GENETIC TECHNIQUES TO CREATE A QUALITY PROFILE OF ANCIENT APPLE CULTIVARS

ABSTRACT

With the diffusion of commercial apple varieties since the second half of the last century, hundreds of different local cultivars rapidly disappeared from orchards in Italy, and the particular quality attributes of these fruits are still at risk of being lost today. The aim of this research was to use sensory, nutritional and genetic techniques in order to define the overall quality of fruits from ancient apple cultivars grown in Northern Italy. Cluster analysis arranged the 10 genotypes into five groups; in most cases, the analyzed cultivars demonstrated higher sensory and nutritional qualities than the control (Golden Delicious cv). The cultivars showed higher values of total polyphenolic compounds and a stronger antioxidant activity. The vitamin C content also differed from the control. The sensory analysis, performed by the Fruit Tasters Italian Organization, was an effective characterization tool and genetic analysis further helped to characterize the identity of these interesting cultivars.

PRACTICAL APPLICATIONS

The characterization and valorization of old apple cultivars are essential to avoid loss of potentially useful germplasm. The reduction of biodiversity of cultivars found in agriculture could lead to problems such as higher susceptibility to widespread outbreaks of plant diseases and pests, and at the same time, the loss of precious source of nutrients. The conservation of apple biodiversity is valuable in order to maintain the gene pool of the species and to introduce superior quality traits into apple‐breeding programs.     

QUALITY ATTRIBUTES, PECTOLYTIC ENZYME ACTIVITIES AND PHYSIOLOGICAL CHANGES DURING POSTHARVEST RIPENING OF NECTARINE

The postharvest ripening at 20C and 90–95% RH for 10 days of ‘Armking’ nectarine grown in a greenhouse was investigated over two seasons. Firmness, titratable acidity, ascorbic acid, pH and maturity index were all adequate to stablish the rate of ripening. However, soluble solids content and reducing and non-reducing sugars showed no significant changes. It took about 10 days for very early ripening fruit (100 g weight and 82 N firmness) and 6 days for normal early ripening fruits (115 g weight and 46 N firmness), both harvested at preclimacteric stage, to become eating ripe (near 20 N). Total weight loss and decay after 10 days was approximately 11%. During ripening there was a temporal coincidence among higher rates of ethyleneproduction, higher pectinmethylesterase (PME) and polygalacturonase (PG) activities, lower firmness and acidity and higher maturity index. PME and PG activities increased during ripening, with a highly negative linear correlation between activities of the two enzymes and firmness. In very early ripening fruit, PME activity was more closely related to softening than PG, whereas in normal early ripeningfruit, PG activity was slightly more closely linked to the loss offirmness than PME.     

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.