Search Results (5)

Shiikuwasha, a citrus fruit native to Okinawa, Japan, has various cultivation lines with distinct free volatile and non-volatile components. However, the glycosylated volatiles, which are sources of hidden aromas, remain unknown. This study aimed to characterize the chemical profiles of free and glycosidically bound volatile as well as non-volatile components in the mature fruits of six Shiikuwasha cultivation lines: Ishikunibu, Izumi kugani-like, Kaachi, Kohama, Nakamoto seedless, and Ogimi kugani. Free volatiles were analyzed using solid-phase microextraction–gas chromatography–mass spectrometry. Glycosides were collected via solid-phase extraction and hydrolyzed with β-glucosidase, and the released volatiles were measured. Additionally, the non-volatile components were determined using non-targeted proton nuclear magnetic resonance analysis. Total free and bound volatiles ranged from 457 to 8401 µg/L and from 104 to 548 µg/L, respectively, and the predominant free volatiles found were limonene, γ-terpinene, and p-cymene. Twenty volatiles were released from glycosides, including predominant 1-hexanol and benzyl alcohol, with Kaachi and Ogimi kugani showing higher concentrations. Principal component analysis (PCA) revealed that taste-related compounds like sucrose, citrate, and malate influenced line differentiation. The PCA of the combined data of free and bound volatile and non-volatile components showed flavor component variances across all lines. These findings provide valuable insights into the chemical profiles of Shiikuwasha fruits for fresh consumption and food and beverage processing. Full article

Shiikuwasha (Citrus depressa Hayata) and calamansi (C. microcarpa Bunge) are distinct citrus species with a strong sour taste that grow naturally in Okinawa, Japan. The present study aimed to characterize the physicochemical traits, total carotenoid content, and taste/nutrient-related metabolite and volatile organic compound (VOC) profiles of the mature fruits from three shiikuwasha cultivation lines (“Izumi kugani”, “Izumi kugani-like”, and “Ogimi kugani”) and calamansi. The shiikuwasha lines had higher ratios of soluble solids/titratable acidity but a lower total carotenoid content than calamansi. There were positive statistical correlations between total carotenoids with red, yellow, and orange indices (a*, b*, and a*/b* color spaces, respectively). Principal component analysis (PCA) revealed that shiikuwasha had higher sucrose and choline contents, while calamansi was richer in sourness-related metabolites such as citrate and malate. PCA plots displayed differences in the VOCs between the two citrus cultivars, wherein volatile accumulation was much richer in juices prepared from the whole fruits than in juices from the edible flesh parts. The plots also showed that monoterpenes and sesquiterpenes differentiated the VOC profiles of shiikuwasha and calamansi. This study reveals differences in the flavor components of the two citrus cultivars and highlights the potential uses of each in local and regional agro-business. Full article

Citrus depressa Hayata is a small-fruit citrus species; it is indigenous to Kagoshima, Okinawa, and Taiwan. The metabolites and volatile organic compounds (VOCs) that affect the flavor of its fruits have not been investigated based on geographical origin. In the present study, we investigated the metabolite and VOC profiles of 18 C. depressa cultivation lines from these regions. Multivariate analysis revealed differences in the metabolites of C. depressa based on its cultivation origins; variations in sugar, sugar alcohol, and amino acid contents were also observed. Fruits from Kagoshima and Okinawa had higher galactinol, trehalose, xylose, glucose, and sucrose intensities than fruits from Taiwan (log₂-fold change; 2.65–3.44, 1.68–2.13, 1.37–2.01, 1.33–1.57, and 1.07–1.43, respectively), whereas the Taiwanese lines contained higher leucine, isoleucine, serine, and alanine. In contrast to the Taiwanese Nantou line, other cultivation lines had comparable total VOC contents, and the VOCs of all lines were dominated by limonene, γ-terpinene, and p-cymene. Accordingly, the highest VOC intensities were recorded in the Nantou line, which was followed by Shikunin sweet (Kagoshima) and Taoyuan (Taiwan) (log₁₀ normalize concentration; 5.11, 3.08, and 3.01, respectively). Moreover, multivariate analysis plots elucidated the difference in the VOCs of Ishikunibu (Okinawa), Shikunin sweet, and Taoyuan and between those of most Kagoshima and Okinawa cultivation lines. These results suggest that both the cultivation line and origin influence the metabolites and VOCs of C. depressa, thus possibly affecting its flavor quality; the data provide a valuable insight for utilizing C. depressa of different cultivation lines and origins to produce foods and beverages. Full article

Citrus depressa Hayata is the native and widespread citrus species in Taiwan. The notable character is that C. depressa has a distinct aroma different from local citrus. The ex situ germplasm of scions from different collection regions has variant leaf shapes and different odor characteristics. Establishing volatile biomarkers for classifying the local C. depressa is beneficial to commercial development. Volatile organic compounds (VOCs) of fresh leaves from seven C. depressa accessions which were collected from different locations in Taiwan were extracted by headspace solid-phase microextraction and analyzed by GC-MS. The volatile compositions from each season showed the diversity, and linalool, of which the average relative content is 52.7%, was the most volatile component in any season. The other main VOCs of leaves of C. depressa were γ-terpinene, limonene, β-ocimene, and α-terpineol. The result of linear discriminant analysis by VOC markers shows that there are two main different types which are (1) accessions from the central and the east of Taiwan and (2) accessions which are closer to C. depressa in Okinawa, Japan. Five major VOC-related synthase genes were selected and the gene expression was used to classify the varieties. The clustering result is the same with VOC-based discrimination. Our results reveal leaf volatile profiling is capable of being the discrimination markers, and the possibility for constructing molecular markers is directly related to characteristics from secondary metabolites phenotyping. Full article

Osteoarthritis (OA), also called degenerative joint disease, is characterized by joint cartilage loss and is strongly linked to obesity. Medicine to alleviate pain is currently the only treatment. Shiikuwasha extract (SE) has been reported to possess valuable bioactive substances exhibiting anti-inflammatory, antiobesity, and anticancer effects. Research is limited to the use of SE in the treatment of OA and obesity. We performed both anterior cruciate ligament transections and medial meniscectomies to induce OA on Sprague–Dawley rats after 11 weeks of a high fat diet followed by 9 weeks of oral SE administration (300, 600, and 1500 mg/kg). This study showed that SE treatment could reduce weight gain and joint pain. Additionally, SE significantly decreased triglycerides and total cholesterol in plasma of the S1500 group but increased high-density lipoprotein cholesterol in the plasma of the S600 group. Meanwhile, plasma levels of tumor necrosis factor alpha (TNF-α) was significantly reduced in the S1500 groups. Histopathological findings confirmed administration of SE attenuated cartilage degeneration. Immunohistochemistry examination demonstrated that caspase 3 and phospho-Janus kinase 2 (p-JAK2) expression levels on chondrocytes were downregulated by SE treatment. Our findings demonstrate that SE can alleviate OA progression by improving obesity. Full article