Emulsion Surimi Gel with Tunable Gel Properties and Improved Thermal Stability by Modulating Oil Types and Emulsification Degree

High resistance to heating treatments is a prerequisite for ready-to-eat (RTE) surimi products. In this study, emulsion-formulated surimi gels were prepared, and the effects of oil types and emulsification degrees on the thermal stability of surimi gel were investigated. The results showed the gel properties of surimi gels were modulated by oil types and emulsification degrees. In detail, the rising pre-emulsification ratio caused the increase of the emulsifying activity index (EAI) and decrease of emulsifying stability index (ESI) for both emulsions. The larger droplet sizes of perilla seed oil than soybean oil may be responsible for their emulsifying stability difference. The gel strength, water retention, dynamic modulus and texture properties of both kinds of surimi gels displayed a firstly increased and then decreased tendency with the rising pre-emulsification ratios. The peak values were obtained as perilla seed oil emulsion with emulsification ratio of 20% group (P1) and soybean oil emulsion with emulsification ratio of 40% group (S2), respectively. Anyway, all emulsion gels showed higher thermal stability than the control group regardless of oil types. Similar curves were also obtained for the changes of hydrogen bond, ionic bond and hydrophobic interactions. Overall, perilla seed oil emulsion with emulsification ratio of 20% (P1 group) contributed to the improved thermal stability of surimi gels.

Physicochemical Characteristics and Thermal Stability of Perilla Seed Oil of Indian Origin

There is an increasing interest of food scientists in finding new alternatives to PUFA rich edible oil. Perilla seed oil (CPSO), an underutilized oilseed, can be used as an edible oil source. Oil extracted by the cold-pressed method from perilla seeds gives a yield of 36.50%. This study reports the physicochemical properties, the oxidative and thermal stability of the cold-pressed perilla seed oil. The viscosity, specific gravity, refractive index, and smoke point of CPSO were 28 m.Pa.s, 0.92, 1.43, and 241 ℃, respectively. The peroxide, acid, iodine, saponification value, and unsaponified matter of CPSO were 4.81 meq O2/kg oil, 1.61 g KOH/kg oil, 132 g KOH/kg oil, 180 g I2/kg oil, and 0.64%, respectively. It consists of high α -linolenic acid (55.80% of total oil) followed by oleic acid (20.54%). The extracted oil is analyzed for its thermal stability (peroxide value, free fatty acids, p- anisidine value, totox value, and total polar compounds) and storage stability for 120 days in two different storage conditions (refrigerated and room temperature). Despite having high nutritional benefits, the oil stability index (0.50 h) of the perilla seed oil is low, limiting its utilization as a frying oil. Therefore, perilla seed oil requires process optimization to increase its stability during heating.

Molecular Mechanism of Antioxidant and Anti-Inflammatory Effects of Omega-3 Fatty Acids in Perilla Seed Oil and Rosmarinic Acid Rich Fraction Extracted from Perilla Seed Meal on TNF-α Induced A549 Lung Adenocarcinoma Cells

Industrially, after the removal of oil from perilla seeds (PS) by screw-type compression, the large quantities of residual perilla seed meal (PSM) becomes non-valuable waste. Therefore, to increase the health value and price of PS and PSM, we focused on the biological effects of perilla seed oil (PSO) and rosmarinic acid-rich fraction (RA-RF) extracted from PSM for their role in preventing oxidative stress and inflammation caused by TNF-α exposure in an A549 lung adenocarcinoma culture model. The A549 cells were pretreated with PSO or RA-RF and followed by TNF-α treatment. We found that PSO and RA-RF were not toxic to TNF-α-induced A549 cells. Both extracts significantly decreased the generation of reactive oxygen species (ROS) in this cell line. The mRNA expression levels of IL-1β, IL-6, IL-8, TNF-α, and COX-2 were significantly decreased by the treatment of PSO and RA-RF. The Western blot indicated that the expression of MnSOD, FOXO1, and NF-κB and phosphorylation of JNK were also significantly diminished by PSO and RA-RF treatment. The results demonstrated that PSO and RA-RF act as antioxidants to scavenge TNF-α induced ROS levels, resulting in decreased the expression of MnSOD, FOXO1, NF-κB and JNK signaling pathway in a human lung cell culture exposed to TNF-α.

Clinical and immunological characterization of perilla seed allergy in children

Background: Perilla seeds are known to cause immediate allergic reactions. However, reports on perilla seed allergies are limited to a few case reports worldwide, and there is currently no diagnostic test for such allergies. Objective: Our objective was to analyze the clinical and immunological characteristics of perilla seed allergy and to identify allergens for the development of diagnostic methods. Methods: Twenty-one children with clinical perilla seed allergy were enrolled from two tertiary hospitals between September 2016 and June 2019. Using perilla seed extract, we developed a skin prick test (SPT) reagent and an IgE enzyme-linked immunosorbent assay (ELISA) for perilla seed allergy diagnosis. IgE immunoblotting was performed for identifying putative allergenic components, and amino acid composition analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: The median age of children with perilla seed allergy was 3 years; the proportion of children with anaphylaxis was 28.6%. Perilla seed SPT was performed in 15 of 21 children, all of whom tested positive. On ELISA, 85.7% of children tested positive for perilla seed-specific IgE. Proteins with molecular weights of 50, 31–35, and 14–16 kDa showed binding with the sera of >50% of children with perilla seed allergy. LC-MS/MS analysis of these three protein fractions indicated 8 putative proteins, including perilla oleosin (Accession No. 9963891), to be allergens. Conclusion: This study documented the clinical characteristics and immunological profiles of 21 children with perilla seed allergy. Our results suggest that oleosin is one of the major allergens in perilla seeds.

Perilla Seed Oil Alleviates Gut Dysbiosis, Intestinal Inflammation and Metabolic Disturbance in Obese-Insulin-Resistant Rats

Background: High-fat diet (HFD) consumption induced gut dysbiosis, inflammation, obese-insulin resistance. Perilla seed oil (PSO) is a rich source of omega-3 polyunsaturated fatty acids with health promotional effects. However, the effects of PSO on gut microbiota/inflammation and metabolic disturbance in HFD-induced obesity have not been investigated. Therefore, we aimed to compare the effects of different doses of PSO and metformin on gut microbiota/inflammation, and metabolic parameters in HFD-fed rats. Methods: Thirty-six male Wistar rats were fed either a normal diet or an HFD for 24 weeks. At week 13, HFD-fed rats received either 50, 100, and 500 mg/kg/day of PSO or 300 mg/kg/day metformin for 12 weeks. After 24 weeks, the metabolic parameters, gut microbiota, gut barrier, inflammation, and oxidative stress were determined. Results: HFD-fed rats showed gut dysbiosis, gut barrier disruption with inflammation, increased oxidative stress, metabolic endotoxemia, and insulin resistance. Treatment with PSO and metformin not only effectively attenuated gut dysbiosis, but also improved gut barrier integrity and decreased gut inflammation. PSO also decreased oxidative stress, metabolic endotoxemia, and insulin resistance in HFD-fed rats. Metformin had greater benefits than PSO. Conclusion: PSO and metformin had the beneficial effect on attenuating gut inflammation and metabolic disturbance in obese-insulin resistance.

The Attenuation of TNF-α-mediated Inflammatory Responses in Human Lung Adenocarcinoma Cell Line by Perilla Seed and Seed Meal Extract

Thai perilla (Perilla frutescens) extracts, which contain a substantial quantity of bioactive substances including phenolics and flavonoids, have shown marked anti-inflammatory activities in several investigated models. In the present study, the effect of perilla seed extract (PSE) and seed meal extract (PSME) on TNF-α-induced inflammatory response in human lung adenocarcinoma A549 cells was investigated. The total phenolic and flavonoid contents in PSME was lower than PSE. Markedly, rosmarinic acid was identified as the main constituent in both extracts. However, the DPPH and ABTS assays indicated that the antioxidant capacity of PSME was equal to PSE. Moreover, the iron-binding activity of PSE and PSME were exhibited by complex formation with Fe3+-NTA, indicating that the extracts may inhibit hydroxyl radical production via Fenton reaction. In vitro cytotoxicity analysis showed that both PSE or PSME co-treated with TNF-α, at 24 h exposure, were not toxic to the A549 cells. Interestingly, PSE and PSME dramatically exhibited an anti-inflammatory activity by inhibiting the mRNA expression of pro-inflammatory cytokines, IL-1β, IL-6, IL-8, and TNF-α, but did not influence iNOS and COX-2 mRNA expressions. Moreover, both extracts significantly reduced reactive oxygen species (ROS) production in TNF-α-induced A549 cells. The findings presented in this paper suggest that PSE and PSME could mitigate TNF-α-mediated inflammatory responses via limiting pro-inflammatory cytokine expressions and decreasing ROS production. Thus, perilla seed and seed meal, the by-product of a perilla seed oil cold-pressed extraction process, could be developed as food supplements or functional foods for the prevention of inflammation-induced lung carcinogenesis development. Keywords: Human lung adenocarcinoma cell line, Inflammation, Perilla seed, Perilla seed meal, Tumor necrosis factor-alpha (TNF-α)