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Sugar alcohols, also known as polyols, have been widely applied in food products for their unique properties. In this work, the effect of soaking treatments composed of the sugar alcohols xylitol, sorbitol, erythritol, lactitol, mannitol, maltitol, and isomaltitol on the quality properties of peeled Pacific white shrimp during frozen storage were evaluated. Samples treated with water and sodium pyrophosphate (Na4P2O7) were designated as the negative and positive controls, respectively. The results indicated that significant improvements were found in thawing, pressing, and cooking loss, myofibrillar protein content, myofibrillar Ca2+-ATPase activity, and textural variables in xylitol- and mannitol-treated shrimp as compared to that of control samples. Water mobility analyses showed that xylitol and mannitol effectively increased the relaxation times T21 and T22 and the percentage of A21 (trapped water) but decreased the percentage of A22 (free water) in muscle tissue. Additionally, the microstructural results indicated that soaking in xylitol and mannitol significantly slowed the damage caused to muscle tissues by large ice crystals. Here, the incorporated xylitol and mannitol molecules presumably replaced water molecules by forming large hydrogen bonds with the muscle proteins, thereby stabilizing their structures in the absence of water while in the frozen state and suppressing the destruction of tissue structure. To note, the lactitol, isomaltitol, and maltitol used in this study did not seem to significantly contribute to cryoprotective effects on shrimp muscle during the experimental period.

Effects of three carrageenan types including κ/ι-hybrid carrageenan, κ/ι-mixture carrageenan, and K + -κ-carrageenan in the concentrations of 0.5 g/kg, 1.5 g/kg, 2.5 g/kg on the texture, rheological property, microstructure, and water holding property of tofu were compared for texture control. Types of carrageenan repeating units affected the coagulation process by changing the protein aggregation behavior in heated soymilk, resulting in the formation of tofu with distinct rheological and water-holding properties. The hardness and elasticity of tofu with κ/ι-hybrid carrageenan were higher. The addition of carrageenan increased the expressible water of tofu without varying its syneresis. The stress relaxation data suggested two relaxation mechanisms in tofu. One appears at a shorter time between 0.4 and 15 s for both λ 1 and λ 2 that represents the aqueous phase with buffering ability in the tofu matrix. The other shows at a longer time around 60–95 s (λ 3 ), that represents the network frame structure in the matrix. The addition of carrageenan increased the λ 3 of tofu, indicating the decrease of network chain mobility. Tofu became softer and less elastic when the concentration of carrageenan was increased. The above phenomenon might be due to the changes in the network structure of tofu by carrageenan. [ABSTRACT FROM AUTHOR]

Abstract: Porous ceramics for anti-heat island effect were prepared from mixtures of allophane and vermiculite (VA samples). Allophane and vermiculite which had been ground for 0.5–2h was mixed in various mass ratios, formed into pellets by uniaxial pressing at 40MPa, and heated at 600–800°C to form porous ceramics. The large thermal expansion of the vermiculite upon explosive dehydration of interlayer water causes cracking of the pellets with higher vermiculite contents. However, this can be controlled by grinding the vermiculite prior to heating. Grinding the vermiculite for ≥2h suppresses its expansion, enabling pellet samples with high vermiculite contents to be prepared without cracking. The bulk densities of samples prepared at 800°C from vermiculite ground for 2h decrease from 1.72 to 0.94 with increasing allophane content. The pore size distribution in these samples shows a distinct peak at about 1μm irrespective of the mixing ratio. The number of smaller pores (<50nm) increases with increasing allophane content while the number of larger pores (20–40μm) increases with increasing vermiculite content. The compressive strengths of the samples range from 1 to 3MPa except for samples containing a high proportion of vermiculite ground for 1h. The water absorption (W a) of the samples increases from 37 to 63% with increasing allophane content. This absorption rate is fast enough to absorb >90% of the W a within 1min for samples of 10mm Ø×5mm3 size. By contrast, the release of the absorbed water is very slow, with 50% of the W a retained for ≥30h in the VA samples at a relative humidity of 55% at 20°C; this is slower than in pure allophane and much slower than in a reference sample of foamed glass (about 4h). All these properties make the VA samples useful as water-retaining materials to combat “heat island” effects. [Copyright &y& Elsevier]