A note on calculating autocovariances of long-memory processes

In this paper, we consider a method (splitting) for calculating the auto- covariances of fractional integrated processes (ARFIMA) and generalized integrated processes (GARMA). The splitting method does not require any restriction on the autoregressive roots, and allows fast calculation of the autocovariances of these processes.     

INTEGRATING SENSORY ANALYSIS AND HEDONIC EVALUATION FOR APPLE QUALITY ASSESSMENT

ABSTRACT

Apple cultivars were subjected to a consumer test in order to appreciate individual preferences and set up a protocol for a practical hedonic‐sensory evaluation. Cultivars subjected to the test were “Golden Delicious,”“Modì,”“Pink Lady” and “Fuji” of two different origins. Apples had the sensory profile defined by a trained panel and were evaluated by 154 consumers. According to their preferences, consumer population could be divided in six clusters. Consumer preference responses clearly associated the two “Fuji” and showed “Modì” and “Pink Lady” to have appeal on the same consumers groups. Besides expressing hedonic judgment, consumers were requested to indicate the positive sensory attributes determining their choice. Consumers appreciated “Golden Delicious” and “Fuji” on the basis of sweetness and aroma, while preferences for “Pink Lady” and “Modì” were expressed by consumers appreciating crispness, juiciness and a certain degree of acidity. The involvement of consumers in defining attributes driving preferences provides details useful for weighing up the consistency between consumers' response and sensory panel profile.

PRACTICAL APPLICATIONS

This work contributes to the knowledge on consumer preferences and concerning apple sensory quality. In particular, the tested varieties could be divided in three groups on the basis of perceived attributes. Knowledge of consumer preferences related to apple qualities can be a key point in planning production and marketing strategies. A protocol integrating sensory characteristics defined by a trained panel, hedonic consumer judgments and sensory preference drivers is proposed.     

Quantitative Crack Surface Morphology of Bone Cements in Relation to Propagation Rate

Morphology of the crack surface of surgical bone cements has seldom been studied in the past despite the clinical relevance of cement failure. Previous studies on a specific cement type suggest that crack morphology depends on crack propagation rate. The objectives of this work were: (i) to develop a quantitative indicator for describing crack morphology; and (ii) to assess if dependency on crack‐propagation rate is affected by cement formulation. Known crack surfaces were obtained from specimens under controlled loading conditions. Crack surface roughness was measured for different crack‐propagation rates, and compared against the amount of cleaved pre‐cured beads (measured with a semi‐automated procedure based on micrographs). Such indicators were extremely robust, operator‐independent, highly correlated, and sensitive to the type of fracture. Moreover, it was found that crack surface morphology heavily depends upon cement composition. Thus, crack surface roughness is proposed as a method for quantitatively identifying crack morphology, and finally classifying fracture type.     

EFFECT OF ANTEMORTEM JOURNEY AND LAIRAGE AT ABATTOIR ON RABBIT MEAT QUALITY

A study was conducted to determine the effects of journey duration (1 versus 3 h) and lairage time at abattoir (0 versus 5 h) on rabbit meat quality traits. Rabbits transported for 3 h produced meat with significantly higher pH values ( P <  0.01), darker (lower L* values, P <  0.01) and less yellow ( P <  0.05) color, as well as lower losses during cooking ( P <  0.01), than those transported for 1 h. Moreover, animals laired for 5 h yielded meat with more ( P <  0.05) yellow color, cooking losses ( P <  0.05) and higher shear values ( P <  0.01) than rabbits not laired before slaughtering. The nuclear magnetic resonance analysis revealed that these differences ( P <  0.05) are mainly related to changes occurring in the distribution of myofibrillar (T₂₁) and extra-myofibrillar (T₂₂) water. In conclusion, this study indicated that journey time and lairage at abattoir may play an important role in determining rabbit meat quality traits.

PRACTICAL APPLICATIONS

In many previous studies that considered the effect of journey and lairage on rabbit meat quality, animals were stress-induced by extreme conditions of journey and/or lairage that were unlikely to occur during commercial operations. The aim of this study is to establish whether meat quality characteristics are still influenced when journey and lairage times match current commercial production practices. Because processing-plant efficiency depends on product uniformity, it will be interesting to test the potential variability effect of rabbit preslaughter practices on meat quality properties.     

PHENOLIC COMPOUNDS AND ANTIOXIDANT POWER IN MINIMALLY PROCESSED SALAD

ABSTRACT

Phenolic content and antioxidant power of Lactuca sativa var. capitata (L.), Cichorium indivia var. latifolium (L.) and Eruca sativa (Mill.) were determined in fresh‐cut products during storage at 4C. In fresh‐cut leaves, storage did not affect the antioxidant power in escarole, whereas after 24 h, lettuce exhibited a transient rise in ferric‐reducing antioxidant power value (+50%), which was associated with increased phenol content. In rocket salad, the antioxidant power increased significantly just 1 h after cutting. The major phenols determined in escarole and lettuce hydroxycinnamic derivatives were chlorogenic acid, di‐caffeoylquinic and caffeoyltartaric acids, which increased significantly in fresh‐cut products of both species during storage. In rocket salad, only hydroxycinnamic and kaempferol derivates were found, and their content was not influenced by processing and storage even if it is probably related to the higher antioxidant power found for this species.

PRACTICAL APPLICATIONS

Many phenolic compounds are antioxidants that may contribute to reduce human diseases (e.g., cancer and heart diseases). The beneficial effects of a diet rich in vegetables have been partially attributed to an increased consumption of phenols with high antioxidant capacity. Processing vegetables (e.g., salad) for minimally processed products influences the antioxidant capacity of the tissues with different effects in relation to the species used.