A series of biscuit‐like model foods that vary primarily in hardness, while keeping other sensory attributes less variable, was developed and used to investigate the relationship between fundamental fracture properties and the sensory perception of hardness of brittle solid foods. Fifteen biscuit samples were evaluated by both a trained sensory panel and three instrumental tests (three‐point bending test, single‐edge notched bend test and modified texture profile analysis), and their relationships were determined by simple linear regression analysis. Correlations revealed that the perceived hardness during biting or chewing is fracture related, and it is directly related to the amount of stress required to initiate and propagate a crack in a material (i.e., fracture stress [σ] and critical stress intensity factor [KIC], respectively). The fracturing of these hard and brittle biscuits appeared to be associated with the release of energy as sound, and thus, the perceived hardness and crunchiness were indistinguishable. PRACTICAL APPLICATIONS Sensory evaluation is time consuming and expensive, and, therefore, reliable and practical (faster, less expensive and reproducible) instrumental methods are needed to accurately predict sensory texture attributes, at least, in the product development and quality control stages. This study demonstrated that the perceived hardness of biscuits can be tracked by σ and KIC with remarkable precision. These properties may be used as a reliable replacement for a sensory assessment of hardness in brittle solid foods, where applicable.

Twenty cereal snack bar samples (10 recipes ¥ 2 oven sides) with a wide range of textural attribute intensities were evaluated by both a trained sensory panel and instrumental methods to determine which instrumental methods accurately predict sensory textural attributes of cereal snack bars in product development and quality control. Very few studies have been devoted to assessing the textural properties of cereal snack bars. We undertook a range of instrumental tests (three-point bending test, cut (shear) test, puncture test, texture profile analysis [TPA] and modified TPA using a probe size smaller than the sample size) using an Instron Universal Testing Machine. Moisture content and water activity of the bars were also measured. Relationships between sensory textural attributes, and instrumental and physical measurements of the bars, were determined by simple regression analysis. Several of the instrumental measurements showed a high degree of correlation (r Ն 0.85, P < 0.001) with some of the sensory textural attributes. Correlations revealed that some of the instrumental measurements could be used to predict the sensory attributes of firmness, chewiness and crumbliness. The compression energy required for the second compression cycle of the modified TPA gave the best prediction of these attributes. Relationships between other sensory textural attributes (sample recovery, return time for springiness, moistness, mouthfeel, adhesiveness to teeth) and instrumental and physical measurements of the bars were less clear. PRACTICAL APPLICATIONSTexture is one of the most important sensory characteristics that determine consumer preference for cereal snack bars and is usually assessed by 1 Corresponding

King salmon (Oncorhynchus tshawytscha) packaged in air (AIR), nitrogen (N2), or 40:60 carbon dioxide:nitrogen (CO2N2) was stored (0 8C) for 18, 25, and 54 d, respectively. Air packs (AIR9) were also stored at 9 8C for 4 d. A quality index (QI) method was developed to monitor sensory quality of cooked salmon. First detection of spoilage was 1.5, 15, 15, and 21 d for AIR9, AIR, N2, and CO2N2 treatments respectively. Total aerobic and sulfideproducing bacteria, pH, drip loss, E h , color, texture, ATP derivatives, trimethylamine, total volatile base nitrogen, thiobarbituric acid numbers, and peroxide values were determined. Only total aerobic counts and hypoxanthine were indicators of sensory deterioration across treatments and times.

Significant differences were found in a wide variety of textural attributes in eight winter squash cultivars (Cucurbita maxima Duchesne) assessed at 4-5 and 9-10 weeks after harvest using both a trained sensory panel and an Instron Universal Testing Machine. The Instron texture profile analysis force-displacement curves were distinctive for each of the eight cultivars tested, with behaviour under deformation forces indicating differences in the structure and composition of the tissue. Starch and logged dry matter contents varied significantly between cultivars, and were strongly correlated with all the sensory textural attributes rated, and with gumminess and hardness (dry matter only) measured by the Instron. Simple linear regressions indicated significant relationships between textural attributes as measured by the sensory panel and the Instron.

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