Determination of the Optimal Concentration of Natural Antimicrobial Agents in Marinade Sauce for Meal Kits

This study aimed to determine the antimicrobial effectiveness of natural antimicrobial agents (NAAs) (yuzu juice, wasabi extract, and rosemary extract) against three target microorganisms (TMs) (Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium) and to determine the optimal concentration of these agents using response surface methodology (RSM) to ensure the safety of meal kits manufactured using marinade sauce. The three NAAs added to marinade sauce effectively inactivated TMs (P<0.05), in particular, yuzu juice had the greatest antimicrobial effect against TMs, followed by wasabi and rosemary extracts. To determine the optimal concentration of NAAs using RSM, 17 concentrations were tested with three TMs as dependent variables and three NAAs as independent variables. The results showed that E. coli was not present under any of the conditions tested, whereas S. aureus and S. Typhimurium exhibited different characteristics depending on the conditions. Through response surface analysis of the TMs except for E. coli, which was not detected, it was determined that S. aureus had a coefficient of determination (R2) of 0.928 and a lack of fit of 0.074, and the linear regression of [yuzu juice] (X1) and quadratic regression of [yuzu juice]2 (X12) were both significant (P<0.05). S. Typhimurium had an R2 of 0.8955 and a lack of fit of 0.051, and only the quadratic regression of [yuzu juice]2 (X12) was significant (P<0.05). Based on RSM and ridge analysis, the optimal mixed conditions were determined to be 3.92% (v/w) yuzu juice, 23.41% (v/w) wasabi extract, and 3.93% (v/w) rosemary extract. After investigating the antimicrobial effect under the optimal conditions, E. coli and S. Typhimurium were absent, and S. aureus was reduced to 2.50 ± 0.09 log colony-forming units/g after 24 h. The results indicated that mixed treatment with the three NAAs had a more significant antimicrobial effect due to their synergistic properties compared to when used in isolation.

A combination of commercial and traditional food-source-derived enzymatic treatment acts as a potential tool to produce functional yuzu (Citrus junos) powder

Enzymatic modifications have been applied in citrus to enhance their physicochemical and biological properties and reduce their bitterness. Notwithstanding, research on the combination of enzyme treatment of yuzu is lacking. In this study, yuzu was treated with a combination of isolated cellulase NY203, pectinase UF, and cellulase KN, and this enzymatic treatment was found to increase monosaccharide, naringenin, and hesperetin levels. In contrast, dietary fiber, cellulose, hemicellulose, lignin, and pectin levels were decreased. Moreover, the enzymes disintegrated the inner and outer surface structures and chemical bonding of yuzu, thus improving its solubility rate, water-holding capacity, oil-adsorption capacity, cholesterol-binding capacity, and water-swelling capacity. Furthermore, NY203 + UF + KN combination treatment reduced the bitterness of treated yuzu by 50 % compared with the control. Additionally, NY203 + UF + KN treatment yielded a 28 % decrease in lipid accumulation and two-fold higher lipolytic activity in 3T3L-1 adipocytes. These findings are potentially beneficial to the food/nutraceutical industries regarding functional yuzu powder production.

Characterization of Odor-Active Compounds of Ichang Lemon (Citrus wilsonii Tan.) and Identification of Its Genetic Interspecific Origin by DNA Genotyping

Ichang lemon is a citrus fruit whose rind gives off a delicious and much appreciated fragrance and flavor. The volatile components of the fruit peel of Ichang lemon were investigated by GC-MS and GC-O (AEDA method). Simultaneously, its genetic origin was identified by using diagnostic SNP markers specific to ancestral species and multiallelic SSR and InDel markers. Ichang lemon combines three ancestral genomes (Citrus maxima, Citrus ichangensis, and Citrus reticulata) and may be a pummelo × Yuzu hybrid. Although the major compounds of the Ichang lemon aromatic profile were present in Citrus junos, a few pummelo-specific compounds were also detected, such as indole and nootkatone, in agreement with its maternal lineage. 3-Methyl-3-sulfanylbutyl acetate, reported to occur in passion fruit and brewed coffee, was identified by GC-MS, GC-QTOF-MS, and GC-FTIR for the first time in citrus. This odor-active compound has a sulfurous, tropical fruity, green note.

Aromatic effects of a Japanese citrus fruit-yuzu (Citrus junos Sieb. ex Tanaka)-on psychoemotional states and autonomic nervous system activity during the menstrual cycle: a single-blind randomized controlled crossover study

BACKGROUND

Yuzu (Citrus junos Sieb. ex Tanaka), a yellow-golden colored citrus fruit, has traditionally been used to promote psychosomatic health in Japan. While the yuzu produces a distinctive, pleasing aroma of citrus and floral, the efficacy of its fragrance remains unknown. The present study investigated the soothing effects of the fragrance of yuzu essential oil from the perspective of autonomic nervous system activity, which plays a crucial role in the integrity of the mind-body connection.

METHODS

Twenty one women in their 20s participated in a single-blind randomized controlled crossover study. Subjects were examined twice each in the follicular and late-luteal phases. Two kinds of aromatic stimulation (yuzu and water as a control) were used. This experiment measured heart rate variability (HRV) reflecting autonomic nervous system activity and used the Profile of Mood States (POMS) as a psychological index before and after the aromatic stimulation.

RESULTS

Only a 10-min inhalation of the yuzu scent significantly decreased heart rate and increased high frequency power of HRV reflecting parasympathetic nervous system activity, regardless of menstrual phase. This significant physiological effect continued for at least 25 min. In addition, the POMS tests revealed that inhalation of the aromatic yuzu oil significantly decreased total mood disturbance, a global measure of affective state, together with two POMS subscales-tension-anxiety and fatigue, as long as 35 min after the aroma stimulation, both in the symptomatic late-luteal and non-symptomatic follicular phases.

CONCLUSIONS

The present study provides the novel information that yuzu's aromatic effects could serve to alleviate negative emotional stress, which, at least in part, would contribute to the improvement of parasympathetic nervous system activity.

Inhibitory effects of yuzu and its components on human platelet aggregation

Our previous study demonstrated that yuzu has an anti-platelet effect in rat blood. In the present study, we examined whether the anti-platelet effect of yuzu can be extended to human blood by investigating its ability to inhibit aggregations induced by various agonists in human platelet rich plasma (PRP). This study also investigated the underlying mechanism of yuzu focusing on ADP granule secretion, TXB2 formations, and PLCγ/Akt signaling. The results from this study showed that ethanolic yuzu extract (YE), and its components, hesperidin and naringin, inhibited human platelet aggregation in a concentration-dependent manner. YE, hesperidin and naringin also inhibited TXB2 formation and ADP release. The phosphorylation of PLCγ and Akt was significantly inhibited by YE, heperidin and naringin. Furthermore, we demonstrated that YE, heperidin and naringin has anti-platelet effects in rat ex vivo studies, and lower side effects in mice tail bleeding time studies. The results from this study suggest that YE, hesperidin and naringin can inhibit human platelet aggregation, at least partly through the inhibition of PLCγ and Akt, leading to a decrease in TXB2 formation and granule secretion.