Snow-storage room (namely yukimuro) is a cooling system that has been used to preserve foods under low temperature and high humidity conditions. In the present study, we investigated the effectiveness of snow utilization for the preservation and ripening of cheese by using a snow-storage room model, which was constructed of a low-temperature, high-humidity refrigerator with crushed ice. When a Camembert cheese was stored in a conventional refrigerator for a month, its water content was significantly decreased not only under air-exposed conditions but also sealed in a gas barrier package. In contrast, the water content of the cheese stored in the snow-storage room model was comparable to that of its initial state even under air-exposed conditions. In addition, both the Camembert and Gouda cheeses stored in the snow-storage room model had good color and texture profiles as compared with those stored in conventional refrigerator. The Camembert cheese stored in the snow-storage room model was preferred by sensory test and showed better evaluation scores regarding color, taste and texture than that stored in conventional refrigerator. Further, the Danish blue cheese stored in the snow-storage room model retained significantly high amount of odor components than that stored in conventional refrigerator. These findings indicate that the conditions in snow-storage room are suitable for preservation and low-temperature ripening of cheese.
Heat-sealing technology, which is used for plastic packaging, entails laminating multiple kinds of films together to form a barrier with varying permeability and stiffness. Creating a heat seal consists of heating the heat-seal material and then immediately cooling it down. However, overheating the heat-seal material can introduce defects such as bubble formation. This study examined the effect of the moisture content on bubble formation by using retort pouches as the sample material. The material is composed of polyester, nylon, and polypropylene as the outermost layer, barrier layer, and heat seal material, respectively. A mechanism of bubble formation is proposed on the basis of the moisture adsorption characteristics, viscous elasticity, and barrier characteristics of the sample material.
Flavor-holding capacities of three surfactants, polyglycerol monolaurate (PGML), sodium dodecyl sulfate, and ovalbumin, were investigated using ethyl acetate, 2-phenylethanol, and geraniol as model flavor compounds. Solid-phase microextraction method was used to determine their concentrations in a gas phase equilibrated with a solution containing the surfactant and flavor compounds. The flavor compounds increasingly dissolved in the solution at the surfactant concentration higher than its critical micelle concentration, except for 2-phenylethanol in an aqueous solution of ovalbumin. Dodecane and glyceryl trioctanoate were added to PGML solutions to understand the contribution of the hydrophobic moiety of the surfactant on the distribution of geraniol in micelles. The addition of dodecane had little effect on the distribution of geraniol. On the other hand, the addition of glyceryl trioctanoate was a little effective. These results suggested that the differences in the flavor holding property of the surfactants are due to the solubilization of these compounds in the amphiphilic region of the surfactant micelles, rather than the hydrophobic region of the surfactants. Solubilization in the ovalbumin solution seemed to be a more complicated phenomenon compared with those in other two surfactants.
Edible thermal-energy-storage (TES) microcapsule was prepared through the formation of complex coacervate. Coconut oil was selected for the core material with its freezing point of ca. 3.3℃ based on the differential scanning calorimetry analysis. The microcapsule containing coconut oil was prepared using a rotor-stator homogenizer through complex coacervation by mixing the oil with gelatin and gum arabic at various oil contents. The microcapsule showed the maximum diameter of 20 μm and higher freezing point (ca. 11℃) than the pure oil. It would be due to the effect of wall material. Because the sticky property of the microcapsule with higher oil contents hindered well-handling, the highest oil content in the microcapsule was practically 67%. The TES capacity of the microcapsule was evaluated using a pseudo food model. The capacity was much higher when the oil content was higher. In addition, microcapsule itself also played a role as a thermal insulator due to the low heat conductivity. When the ambient air temperature changed between -7.2 to 39℃, the microcapsule containing 67% oil exhibited its TES capacity, and the temperature of the pseudo food ranged between 3.6 to 29℃. Although the temperature range was relatively wider, this result indicates the development of the edible TES microcapsule.
The goal of this study is to construct a novel robot system for constant quantity filling cans (fixed can- filling task) in fish-processing plants. In this paper, we will demonstrate first a novel algorithm for the proper combination of a grilled fillet’s body and tail part as defined by the combined weight. As a result, the discrimination of experienced workers based only on combinations of visual information produced a correct answer rate of approximately 50%; the correct answer rate rose to about 90% when the sensation of weight obtained by grasping the grilled fillets could be used. On the other hand, a rate of approximately 95% correct answers was obtained by the proper combination algorithm based on the proposed three-dimensional feature that could quantify grilled fillets. Secondly, we will demonstrate the experimental verification of our novel robot system to select a pair of grilled fillet’s body and tail parts using the proper combination algorithm. This robot system consists of three linear-motion sliders in the X-Y-Z direction with a customized hand mechanism based on SWITL technology. As a result, our novel robot system for fixed can-filling task requires approximately 30 sec for picking up and transporting a pair of grilled fillets to the can. The system had 75% working accuracy despite skilled workers scoring 90%. Although the proposed robot system should improve the working accuracy and its speed of movement, these results suggest that our novel robot system for fixed can-filling task by installing the proper combination discrimination algorithm could replace the work of skilled workers in fixed can-filling.
Potato starch was rendered digestion resistant by the addition of fatty acids (lauric, myristic, palmitic, stearic, oleic, or linoleic) and heat treatment. The effect of different fatty acids on starch digestibility was investigated, as well as the relationship between digestibility and the quantity of fatty acids able to form starch complexes. Although myristic acid reduced digestibility by the greatest degree in samples adjusted to 15% moisture content, no significant difference (p＜0.05) among fatty acid types was observed in samples adjusted to 20% moisture content. Digestibility tended to decrease with increasing internal free fatty acid (IFFA) content up to 4 mg per 1 g of starch (dry basis) but did not change substantially for IFFA content greater than 4 mg. This result suggests that starch-fatty acid complex formation reaches saturation when IFFA content is approximately 4 mg and that further addition of fatty acid has no remarkable effect on digestibility.