蛍光指紋イメージングによる食品中成分の可視化

学位の種別:課程博士University of Tokyo(東京大学

Influence of micro wet milling parameters on the processing of Komatsuna ( Brassica rapa var. perviridis ) juice with rich phosphatidic acid

The aim of this work was to study the effects of multiple micro wet milling (MWM) parameters on particle size reduction and phosphatidic acid (PA) content enrichment of Komatsuna juice. Through an investigation of MWM milling characteristics for Komatsuna juice with different milling conditions, the results showed that milling time, milling rotational speed, gap size, material feeding rate, and interactions among the milling parameters had different significant effects on reduction in particle size. Furthermore, reduction in particle size strongly promoted the increase of PA content in the milled Komatsuna juice, which could improve the bioaccessibility of PA that converts to lysophosphatidic acid in the GI tract for the restoration of GI disorders. The MWM system was able to produce Komatsuna juice with a smaller particle size (approximately 21 μm) and a higher PA content (approximately 70 μg/mL) in a continuous processing system compared to an ordinary grinding mixer

Effect of gum arabic-modified alginate on physicochemical properties, release kinetics, and storage stability of liquid-core hydrogel beads

Different weight ratios of alginate/gum arabic (GA) solutions were prepared to serve as the wall material of liquid-core hydrogel beads (LHB) that were formulated to protect the total phenolic compounds (TP) of radish by-product juice from degradation during storage and release in simulated gastrointestinal fluid. The diameter of LHB ranged from 4.63 to 5.66 mm with a sphericity lower than 0.05. LHB formulated with 25% GA (AGB0.25) exhibited the highest hardness (26.63 N), and those formulated with 50% GA (AGB0.50) exhibited the highest loading efficiency (86.67%). AGB0.25 was effective in preventing TP from degrading during storage with a decay rate (k) of 6.10 × 10−3 day−1 and a half-life (t1/2) of 113.63 days, it showed the slowest release of TP in simulated gastric fluid (k = 2.25 × 10−6), and the release mechanism followed Fickian diffusion. The results suggest that GA is effective in improving the physicochemical properties of alginate

Utilization of Fermented Rice Milk as a Novel Coagulant for Development of Paneer (Soft Cheese)

In this study, fermented rice milk was used as a novel coagulant for a type of soft cheese named as paneer. Rice milk was produced by a wet milling system in a process where brown rice was first soaked in water at a ratio of 1:2 (w/w), then milled by micro wet milling. Rice milk was pasteurized and gelatinized followed by the saccharification and lactic acid fermentation process. Paneer was produced using whole dairy milk mixed with 10%, 20%, and 30% of simultaneous saccharified and fermented (SSF) rice milk as a coagulant, and was analyzed for its physicochemical, microbial, and sensory properties. The results indicated that fermented rice milk has constructive effects on the physicochemical properties, texture, and shelf life of paneer, as there were no obvious defects observed for up to 12 days of storage at 4 °C. The sensory evaluation revealed that the acceptability score of the samples containing rice milk reduced slightly compared to the control samples. No significant differences (p ≤ 0.05) were observed among all the paneer samples incorporated with different percentages of rice milk, and the product was rated acceptable

Nondestructive Evaluation of Wet Aged Beef by Novel Electrical Indexes: A Preliminary Study

The aim of this study was to investigate the suitability of electrical impedance spectroscopy (EIS) as a nondestructive quality monitoring tool of aged beef, focusing on the development of accurate electrical indexes. The relationship between the electrical indexes derived from the impedance ratio (IR) or admittance was established. Quality parameters such as the drip loss, cooking loss, water-holding capacity, and shear force of beef loin wet-aged for 0 to 21 days were evaluated to develop the new electrical indexes. In addition, the predictive capability of EIS was trialed using different indexes and frequencies. This study revealed that the most appropriate choice is to use electrical parameters at a lower frequency to determine or predict the physical properties of aged beef. The IR was derived from the ratio between the electrical impedance measured parallel to and perpendicular to the muscle fibers in the low-frequency domain. Furthermore, the degradation of muscle fibers was observed by optical microscopy. The investigated electrical indexes had higher correlations with shear force (0.52 ≤ R2 ≤ 0.58) compared to correlations with aging days (0.34 ≤ R2 ≤ 0.39). The findings of the study could be used for meat quality inspection in slaughterhouses as well as during aging

Effect of Slightly Acidic Electrolyzed Water Immersion at Different Frequencies on Quality of Raw Chicken Legs

Slightly acidic electrolyzed water (SAEW) is used as a disinfectant for raw chicken meat. Because its volume for a single immersion exceeds 10 times the weight of meat, a large amount of wastewater is generated. Importantly, a higher frequency of immersion is believed to reduce microbial contamination. The objective of this study was to investigate the effect of SAEW immersion at different frequencies on the disinfection and quality of raw chicken legs, thereby possibly limiting the usage of SAEW. Immersion for 1, 3, and 5 times, with a 7:1 SAEW:meat ratio, and duration of 15 min was tested. Meat quality was evaluated based on total aerobic bacteria, Enterobactericeae, total volatile basic nitrogen, thiobarbituric acid reactive substances, and color. A higher immersion frequency lowered the numbers of total aerobic bacteria and Enterobacteriaceae. Moreover, two immersions with a SAEW:meat ratio of 4:1 and a total immersion time of 6 min reduced the bacterial load as effectively as a single 15-min immersion with a SAEW:meat ratio of 7:1. Higher frequencies of SAEW immersion also resulted in lower total volatile basic nitrogen and lipid oxidation after 0 or 3 days of storage. They did, however, magnify the change in color, resulting in brighter meat. Overall, SAEW treatments with two to five immersions can improve the quality of raw chicken legs and reduce wastewater generation

Preparation and physical property assessments of liquid-core hydrogel beads loaded with burdock leaf extract

Secondary gelation is an important but overlooked element which has a significant impact on the quality of liquid-core hydrogel beads (LHB). This study firstly searches the optimized extraction conditions of burdock leaf and analyses its functional compounds and antioxidant abilities. Then, we measure loading efficiency, relative hardness, swelling capacity, and outer appearance to evaluate the optimized preparation conditions of LHB loaded with burdock leaf extract (BLE). The results showed that the optimized extraction conditions of burdock leaf were a solid to liquid (95% ethanol) ratio of 1:3, and extraction at 80 °C for 90 min. This extraction contained 23.81 mg g-1 dw chlorogenic acids (CGA) and the DPPH scavenging activity was 59.49%. LHB prevented the DPPH scavenging ability of BLE from decreasing during storage. The diameter and swelling capacity of burdock LHB increased, and hardness and loading efficiency decreased with longer gelation times. Relative hardness of the LHB prepared by 1% CaCl2 in the secondary gelation was 5.6-fold higher than that of the control, but there was no significant difference in CGA loading efficiency

Evolution of the bulk optical properties of bovine muscles during wet aging

The bulk optical properties (BOP) of two bovine muscles were studied in the 500nm to 1850nm wavelength range. Over a two-week period of wet aging, the BOP of the biceps femoris (BF) and longissimus lumborum (LL) were determined and related to moisture content, tenderness and cooking loss. The absorption by myoglobin and reduced scattering coefficient were higher in the BF compared to the LL. The scattering anisotropy factor was relatively high (>0.95 for LL), representing dominant forward scattering. Two-toning effects in the BF could be attributed to significant scattering differences, as no differences in absorption properties were observed. During wet aging, the anisotropy factor decreased, while tenderness increased. It was hypothesized that this might be related to proteolysis of cytoskeletal proteins. The results show the potential use of BOP to monitor tenderization and the cause of color differences in beef muscles. Moreover, this information could be used to develop and optimize optical sensors for non-destructive meat quality monitoring.status: publishe