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The aroma and texture of three different apple cultivars, harvested at three maturity stages, were analyzed by sensory and instrumental analysis. The emphasis was on the identification of the most potent odorant volatiles, and the challenge was to separate the few most important flavor compounds, which may be trace chemicals, from the vast number of nonodorant compounds present in apple aroma extracts. Thirty-six odorant compounds were detected, 24 of which were common to all extracts. A significant correlation coefficient was found between the aroma intensity scores and overall quantity of the odorant volatiles, which shows that the development of sensory aroma is similar to that of odorant volatiles. This study also showed that the parameters measured by penetrometry and compression were highly correlated with sensory textural attributes. The determination of the optimal maturity stage for different apple cultivars by the usual parameters, such as color, diameter, total soluble solids, and titrable acidity, may not be sufficient to determine the optimal sensory quality for consumers. Moreover, the sensory quality of fruits changes during maturation in a different way from one cultivar to another, and this should be taken into account.

Texture analysis is a well-established analytical technique in the food industry for evaluating the mechanical and physical characteristics of both raw ingredients and finished products. Instrumental mechanical properties of table grapes, acquired using universal testing machines equipped with specific probes, may be of interest in the viticulture and postharvest sectors to recognize the potential of each variety and help satisfy market requirements. The measured parameters are related to some sensory properties and, therefore, indirectly to consumer acceptability of the product. As texture analysis is a rapid and low-cost analytical technique, it can also be favorably applied in enology as a routine tool for monitoring winegrape quality. Among the different mechanical parameters measurable, berry skin thickness and hardness are indices that reflect anthocyanin extractability and dehydration kinetics with adequate reliability. This review collects the most recent research results from grape texture studies, emphasizes the potentiality and limits of this analytical technique when applied to grape studies, and highlights trends that require further understanding.

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There is scant literature on the assessment and validation of methods for monitoring grape texture during ripening. There is a distinct lack of information from published work on the correct procedures to set up texture method. If the measurement of grape texture is to be used for assessing ripeness and further extended to the assessment of polyphenol extractability potential, the relationship between physicochemical parameters and sensory descriptors should be evaluated as a matter of importance. In this work, the physical properties of grape texture during ripening were addressed by an assessment of the relationship between the methods of double compression and puncture tests. The second part of the study reported here applied the methods developed in the first year to grapes sampled in the following year. The results showed that the mechanical texture measurements were able to discriminate grapes coming from different parcels and correlations were found between texture parameters and sensory descriptors. PRACTICAL APPLICATIONSThis paper defines the measurement conditions for monitoring grape texture, particularly during ripening. These established methodologies provide enologists with the tools to monitor the progress of grape maturity, and these mechanical methods compare favorably with the expensive and timeconsuming classical methods. These established methodologies could also be 1 Corresponding Journal of Texture Studies 40 (2009) 511-535. © 2009 used to highlight important information on grape evolution during ripening and help to provide better insight on the choice of the preferred/ideal harvest date. These tools, providing enologists with data on the evolution of fruit texture, could be used to help select more suitable winemaking processes as well, as the extractability of compounds present in the fruit is probably linked to its texture.

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