Crispness and crunchiness are important factors in the enjoyment of many foods, but they are defined differently among dictionaries, consumers, and researchers. Sensory, mechanical, and acoustic methods have been used to provide data on crispness and crunchiness. Sensory measurements include biting force and sound intensity. Mechanical techniques resemble mastication and include flex, shear, and compression. Acoustical techniques measure frequency, intensity, and number of sound events. Water and oil content contribute to crispness and crunchiness, which also have temporal aspects. Information in the literature is compared in this article to develop definitions of crispness and crunchiness.A dense-textured food which, when chewed with the molars, undergoes a series of fractures while emitting relatively loud, low-pitched sounds. CONCLUSIONSFurther work on differentiating and defining crispy and crunchy textures is needed so that universal standards can be obtained. Such definitions could be translated into any 960 TUNICK ET AL. language and would be applicable to fruits, vegetables, baked foods, extruded foods, etc. Research in our laboratory, described in a subsequent article, [74] represents a step in that direction.

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Thirty-one samples of vegetable oils were analyzed for free fatty acid (FFA) concentration by titration against sodium hydroxide and by trimethylsilyl (TMS) derivatization followed by gas chromatography (GC). In preliminary experiments, two silylation chemistries and three GC stationary phases were tested for TMS fatty acid ester formation and separation. No ideal combination of conditions was identified; however, hexamethyldisilazane with an acid catalyst and a non-polar J & W DB-5 column were chosen for comparison of the two approaches. Over the range of FFA values studied (0.04-12%), the results from the two methods were highly correlated (R > +0.996) and were generally in good agreement. However, values from the chromatographic method were slightly lower than values obtained by titration for the crude oil samples (which had higher FFA levels). For oils with >0.4% FFA, the GC approach was slightly less reproducible (average coefficient of variance of~3%) compared with the titration approach (average coefficient of variance of~1.4%). For oils with <0.4% FFA, the coefficients of variance were higher (8-9%) and comparable between the methods.

Adding whey protein concentrate (WPC80) and cashew pulp (CP) to extruded snacks can reduce overall carbohydrate content. In this study, barley, cassava, corn meal and quinoa were blended with WPC80 (12.5 wt%) or with CP (12.5 wt%), then extruded and baked. The products' rapidly available glucose values or potential glycemic index were: quinoa (70%), barley (61%), corn (54%), and cassava (48%). Adding WPC80 with or without CP improved the glycemic potential values for barley and quinoa, but not for cassava, which increased from 61 to 77%. Adding WPC80 or CP had no effect on corn products.