Sang In Kang

Scallops, an economically important seafood, are popular as fried snacks. Vacuum low-temperature frying creates crispy, healthier foods that meet consumer demand for nutritious snacks with excellent texture. However, research on vacuum frying for shellfish products remains limited. This study aimed to optimize the process for developing a healthy, crispy snack that retains the original shape of the Yesso scallop (Patinopecten yessoensis) adductor muscle using vacuum low-temperature frying technology. The effects of various frying methods on the scallops were analyzed. The vacuum low-temperature frying process was optimized based on evaluations of physical, chemical, and sensory properties. Frying conditions were optimized using response surface methodology, with temperature (X1: 90.1–109.9 °C) and time (X2: 186–774 s) as variables. Based on moisture (5.6 ± 0.1 g/100 g), hardness (1470 ± 5.0 g/cm²), and sensory chewiness (7.6 ± 0.2 points) analyses, 99.9 °C and 480 s were identified as the optimal conditions. Validation was conducted through sensory evaluation by 30 trained panelists. Scallops produced under these optimal frying conditions exhibited low water activity (aw) (0.46), desirable texture (1428 g/cm²), palatability (7.9 points), and high protein content (45.6 g/100 g). The predicted and experimental values for frying temperature and time showed strong agreement, validating the reliability of the optimization model.

Surimi-based products typically demand cold storage and a cold chain distribution system, which not only affects their physical properties and flavor but also escalates production costs. In this study, we introduced a novel high-temperature and high-pressure retort processing method to enable room temperature storage and distribution of a surimi-based product, a fish paste cake. Our optimization efforts focused on refining the processing conditions for the fish paste cake. This included incorporating transglutaminase, sugar additives, natural herbal or seaweed extracts, and optimizing retort processing conditions to enhance textural properties, minimize browning and off flavor, and extend the shelf-life of the product. Our results demonstrated that the addition of 0.3% ACTIVA TG-K, 1.0% trehalose, and 0.5% sea tangle extract during the production process significantly enhanced the gel strength, minimized browning, and improved the overall flavor of the fish paste cake prototype. Importantly, the developed prototype exhibited favorable biochemical, textual, nutritional, and sensory properties, extending the shelf-life up to 160 days without compromising physical, chemical, or sensory attributes. In addition, the developed prototype exhibited improved elasticity, compared to control groups. The innovative process not only facilitates room temperature storage and distribution of surimi-based products but also holds potential for generating additional profits.

Muscle atrophy is a detrimental and injurious condition that leads to reduced skeletal muscle mass and disruption of protein metabolism. Oyster (Crassostrea nippona) is a famous and commonly consumed shellfish in East Asia and has become a popular dietary choice worldwide. The current investigation evaluated the efficacy of C. nippona against muscle atrophy, which has become a severe health issue. Mammalian skeletal muscles are primarily responsible for efficient metabolism, energy consumption, and body movements. The proteins that regulate muscle hypertrophy and atrophy are involved in muscle growth. C. nippona extracts were enzymatically hydrolyzed using alcalase (AOH), flavourzyme (FOH), and protamex (POH) to evaluate their efficacy in mitigating dexamethasone-induced muscle damage in C2C12 cells in vitro. AOH exhibited notable cell proliferative abilities, promoting dose-dependent myotube formation. These results were further solidified by protein expression analysis. Western blot and gene expression analysis via RT-qPCR demonstrated that AOH downregulated MuRF-1, Atrogin, Smad 2/3, and Foxo-3a, while upregulating myogenin, MyoD, myosin heavy chain expression, and mTOR, key components of the ubiquitin–proteasome and mTOR signaling pathways. Finally, this study suggests that AOH holds promise for alleviating dexamethasone-induced muscle atrophy in C2C12 cells in vitro, offering insights for developing functional foods targeting conditions akin to sarcopenia.

Fish head byproducts derived from surimi processing contribute about 15% of the total body weight, which are beneficial to health because they contain essential nutrients. In this study, olive flounder (OF) was the target species in order to maximize the byproduct utilization. In RAW 264.7 macrophages, the seven hydrolysates from OF head byproducts were examined for their inhibitory potential against inflammation and the oxidative stress induced by lipopolysaccharides (LPS). The pepsin hydrolysate (OFH–PH) demonstrated strong anti-inflammatory activity via the down-regulation of NO production, with an IC50 value of 299.82 ± 4.18 µg/mL. We evaluated the inhibitory potential of pro-inflammatory cytokines and PGE2 to confirm these findings. Additionally, iNOS and COX-2 protein expressions were confirmed using western blotting. Furthermore, the results from the in vivo zebrafish model demonstrated that OFH–PH decreased the LPS-elevated heart rate, NO production, cell death, and intracellular ROS level, while increasing the survival percentage. Hence, the obtained results of this study serve as a platform for future research and provide insight into the mediation of inflammatory disorders. These results suggest that OFH–PH has the potential to be utilized as a nutraceutical and functional food ingredient.

We prepared a long-arm octopus Jangjorim prototype (LOJP) by optimizing the ratio of ingredients for seasoning and establishing heat sterilization parameters. The optimal amounts of purified water (2.9–56.6%, A), starch syrup (0.3–37.8%, B), and soy sauce (25.5–71.5%, C) for the production of seasoning soy sauce were obtained using response surface analysis. The LOJP was prepared by combining A, B, and C under the optimal conditions and evaluated for consumer preferences and physicochemical, nutritional, and microbiological properties and compared with Korea’s legal management standards for geriatric nutrition. The hardness of the LOJP produced using the optimal mixing ratio of purified water (51.2%, 154.0 g), starch syrup (29.3%, 308.0 g), and soy sauce (19.5%, 256.9 g) was 36.7 × 1000 N/m². This value was lower than the hardness of raw octopus (2153.6 × 1000 N/m²) by 2116.9 × 1000 N/m². It received the highest score (8.7) in the preference evaluation of older consumers. The LOJP was classified as level 2, allowing consumption through the gums of elderly consumers per Korea’s food standards for the elderly. The LOJP was the product highly preferred by elderly consumers with chewing disorders due to its ease of intake and nutritional content.

Modern consumers, especially the elderly, have a keen interest in healthy food choices. This study was conducted with the objective of developing squid paste sausages that are easily consumable by elderly individuals while also fulfilling their nutritional requirements. Response surface methodology (RSM) was employed to determine the ideal proportions for mixing raw common squid (RCS; 2.9–56.6%, A), isolated soy protein paste (ISPP; 0.3–37.8%, B), and surimi paste (SP; 25.5–64.7%, C) in order to create a common squid paste sausage prototype (CSPSP). The CSPSP underwent a comprehensive evaluation, encompassing its physicochemical, nutritional, and microbiological attributes, as well as consumer preferences, and was compared to Republic of Korea’s standards for senior-friendly foods. The optimal mixing ratios derived through RSM were as follows: RCSF, 38.7%; ISPP, 21.2%; and SP, 40.1%. Consequently, the hardness of CSPSP (CSPSP-A) prepared with these ratios was measured at 27.8 × 1000 N/m², a remarkable 95.0% reduction compared to CSPSP-N. Moreover, the texture preference for CSPSP-A was rated at 8.5, signifying the highest level of preference. As a result, CSPSP-A earned a second-grade rating, indicating its suitability for safe consumption by elderly individuals with chewing disorders.

Olive flounder (OF) is a widely aqua-cultivated and recognized socioeconomic resource in Korea. However, more than 50% of by-products are generated when processing one OF, and there is no proper way to utilize them. With rising awareness and interest in eco-friendly bio-materialization recycling, this research investigates the potential of enzymatic hydrolysis of OF by-products (OFB) to produce functional ingredients. Various enzymatic hydrolysates of OFB (OFBEs) were generated using 11 commercial enzymes. Among them, Prozyme 2000P-assisted OFBE (OFBP) exhibited the highest protein content and yield, as well as low molecularization. The muscle regenerative potential of OFBEs was evaluated using C2C12 myoblasts, revealing that OFBP positively regulated myoblast differentiation. In an in vitro Dex-induced myotube atrophy model, OFBP protected against muscle atrophy and restored myotube differentiation and Dex-induced reactive oxygen species (ROS) production. Furthermore, zebrafish treated with OFBEs showed improved locomotor activity and body weight, with OFBP exhibiting outstanding restoration in the Dex-induced muscle atrophy zebrafish in vivo model. In conclusion, OFBEs, particularly OFBP, produce hydrolysates with enhanced physiological usability and muscle regenerative potential. Further research on its industrial application and mechanistic insights is needed to realize its potential as a high-quality protein food ingredient derived from OF processing by-products.

Considering the need for developing new senior-friendly processed seafood, this study aimed to develop octopus pulpo with high preference and excellent quality characteristics for elderly individuals by optimizing the vinegar immersion and sous vide softening treatment conditions for octopus (Octopus vulgaris) arms. The optimal sous vide heating temperature (70.0–100.0 °C), time (69.5–170.5 min), and vinegar concentration (0.2–0.8%) were established using response surface methodology (RSM). The pulpo prototype was produced using an octopus arm softened under optimal conditions and seasoned with a potato and olive oil sauce. The physicochemical and nutritional properties of the prototype were evaluated, followed by sensory evaluation and safety assessments. The hardness of softened octopuses obtained by 0.48% vinegar immersion and sous vide treatment (84.3 °C, 139.8 min), determined using RSM, was 394.5 × 1000 N/m², showing a reduction of 83.0%; this was confirmed by electron microscopic observation. The texture of the pulpo prototype with softened octopus arms showed the highest preference (8.4 points) and high physicochemical and nutritional properties. Overall, the octopus pulpo a La Gallega prototype produced using texture-modified octopus arms was suitable for consumption by elderly people with chewing disorders and could help improve their quality of life.