Nicholas P. Latona

CRITICAL EVALUATION OF CRISPY AND CRUNCHY TEXTURES: A REVIEW

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.

Choline chloride based ionic liquid analogues as tool for the fabrication of agar films with improved mechanical properties.

In the present paper, we test the suitability of ChCl/urea (DES-U) and ChCl/glycerol (DES-G) eutectic mixtures, each one prepared at 1:2 molar ratio, for the production of agar films. A three-step process is proposed: pre-solubilization of polymer in DES followed by compression-molding and subsequent drying. The mechanical properties, water resistance and microstructure of the films were evaluated at different polymer concentrations (i.e. 2-6%, w/w). DES-U showed by far, the best film forming ability. Agreeing with the diffusion and SEM data, films with the best mechanical properties were found at the lowest and highest agar concentrations (tensile strengths of 24.2-42 MPa and elongations of 15.4-38.9%). The water sorption and contact angle studies suggested increased hydrophilicity for the film containing the lowest concentration of agar. The use of choline chloride based ionic liquid analogues as solvent and plasticizer might be a promising tool for the development of new non-aqueous materials based on seaweed polysaccharides.

Acoustic emission studies on the lubrication of a fibrous collagen material-leather

For thousands of years, collagen materials, such as leather, have been among the most dominant natural fibrous materials used by humans. Fatliquoring is one of the critical steps in the leather-making process, wherein oil or a lubricant is added to the leather to prevent the leather fibers from sticking together, thereby providing sufficient pliability to the leather. We have examined the feasibility of using the acoustic emission (AE) technique to characterize the degree of lubrication of leather produced with various fatliquor concentrations. In a tensile test, an acoustic transducer was contacted with the leather samples to collect their AE quantities and properties. The samples lubricated with a fatliquor concentration less than 10% showed twin peaks on the plot of hits rate versus time. This implied that a non-uniform fracture occurred in a leather structure that was not sufficiently lubricated. In contrast, a sufficiently lubricated leather structure showed a steady increase in hits rate with time until it fractured. Traditional stress-strain tests did not reflect these behaviors. Observations also showed a direct correlation between the cumulative hits and fatliquor concentration. The results of this work may provide a route to identify an adequate degree of lubrication in the leather.

Instrumental Textural Perception of Food and Comparative Biomaterials

Exposing an extruded corn snack, an extruded biodegradable packing material, carrots, and wood chip cork to relative humidity conditions ranging from 29.5 to 97.5% changed their moisture content and affected the respective internal structures. The extruded corn snack and extruded biodegradable packing material specimens evaluated after 24 h, absorbed moisture and lost crispness. Carrot and cork specimens were evaluated after 48 h; carrots lost moisture, became softer, and decreased in hardness from 55.02 ± 7.59 to 23.6 ± 8.6 N, while cork specimens were unchanged. For all products, loss of moisture increased surface roughness. Increasing moisture amplified turgidity and strength in extruded biodegradable packing material, decreased crispness in extruded corn snack, and stiffness in carrot, but produced no changes in the wood chip cork.