Comparative study for metabolomics, antioxidant activity, and molecular docking simulation of the newly bred Korean red rice accessions.

This study analyzed the metabolite profiles and antioxidant capacities of two waxy and non-waxy Korean red rice accessions newly bred. Fifteen phenolic compounds were detected in the rice samples. Accession1 had high fatty acids, phytosterols, and vitamin E; accession3 had high vitamin E and phytosterol; and accession4 had a high total flavonoid. The correlation analysis findings from this study validated the positive association between all the metabolites and antioxidant activity. in silico results revealed that protocatechuic acid had a docking score of -9.541, followed by luteolin, quercetin, and caffeic acid, all of which had significant docking scores and a significant number of contacts. Similarly, molecular dynamics simulations showed that phytochemicals had root mean square deviation values of <2.8 Å with Keap 1, indicating better stability. This study provides valuable insights into potential directions for future investigations and improvements in the functional qualities of other colored rice varieties.

Geographical origin discrimination of Agaricus bisporus produced by the complete medium: A pilot study in South Korea.

The complete medium used for mushroom cultivation is important for reliable crop production. We aimed to identify how the origin of Agaricus bisporus grown in Korea was affected by complete media produced in different geographical regions using stable isotope ratios (SIRs). We found that the SIR features of A. bisporus significantly depended on the complete media origin used; in particular, it appeared the high δ34S in the Chinese complete medium, low δ34S in the Dutch complete medium, and high δ15N in the Korean complete medium (P < 0.05). The support vector machine method appeared better geo-origin classification of A. bisporus by the complete media compared to a linear discriminant analysis. A large-scale study should be conducted to establish a reliable origin identification model for A. bisporus grown in complete media to improve the global mushroom marketplace.

Improved accuracy of geographical origin identification of shiitake grown in sawdust medium: A compound-specific isotope model-based pilot study.

In countries like South Korea and the USA, origin labeling of shiitake grown using imported Chinese-inoculated medium is an issue. Therefore, we evaluated the use of compound-specific isotope analysis (CSIA) for the accurate identification of the geographical origin of shiitake (Korean, Chinese-inoculated medium, and Chinese); Chinese-inoculated medium shiitake were cultivated in Korea using inoculated sawdust medium from China. The CSIA-discriminant model showed an overall accuracy of 100% in the geographical classification of the original set and 96.4% for the cross-validated set. Glutamate and aspartate δ15N values were the most important variables for differentiating shiitake based on their origins. Compared to that observed upon using the bulk stable isotope analysis, the CSIA model was associated with significantly improved predictability of origin identification. Our findings elucidate the importance of isotope signatures in developing a reliable origin labeling method for shiitake cultured on the sawdust medium for the global market.

Long-term isotopic model study for ecofriendly rice (Oryza sativa L.) authentication: Updating a case study in South Korea.

To overcome the lack of consumer trust in ecofriendly products due to low reliability of ecofriendly certification and decreasing areas certified for growing ecofriendly agricultural products, alternative approaches for reliable certification are required. Isotopic-chemometric analysis has potential for determining organic authenticity, but previous studies have struggled to differentiate the authenticities of different rice types. The present study examined 5-year variations in δ13C and δ15N in ecofriendly and conventional rice sold at retail markets in South Korea, while assessing the feasibility of discriminant models for authentication of organic rice. Supporting vector machine analysis showed 4.4-14.6% better overall predictability of rice types than discriminant analysis and was effective in discriminating organic or conventional rice from pesticide-free rice, potentially enabling high-throughput screening to authenticate organic rice at marketplaces. Our findings provide reliable information for authenticating ecofriendly rice, with a potential to improve consumer safety and thus the confidence in organic products.

An origin identification model for labeling of shiitake (Lentinula edodes).

With the increasing globalization of the food trade across countries and continents, reliable identification of the geographical origin of products is critical. In this study, we describe the limitations of the current origin labeling system for non-soil-based agricultural products and suggest alternative strategies for the identification of the geographical origin of such products. An origin identification model based on stable isotope ratio analysis combined with discriminant analysis is used to evaluate the similarities and dissimilarities between domestic and foreign shiitake mushrooms, including Chinese inoculated sawdust blocks and Chinese origin. The results show a classification sensitivity of 92.0%, classification specificity of 91.5%, and overall accuracy of 93.5%. In particular, δ15N was the most important isotope marker for the identification of the origin of shiitake mushrooms. Hence, the current origin labeling system for mushroom species has to be revised to establish fair trade and avoid improper origin labeling in the global shiitake market.

Regional Characterization Study of Fatty Acids and Tocopherol in Organic Milk as a Tool for Potential Geographical Identification.

Reliable geographical identification can protect producers of excellent agroproducts, and also provide reliable purchasing information to satisfy consumers. Therefore, this study aimed to evaluate the regional and monthly variation in fatty acid (FA) and tocopherol (TOC) in organic milk (OM) and develop a geographical discriminant model of OM in Korea. In this study, OM had α-TOC and showed a regional or monthly difference of 3-5%. Moreover, C16:0, C18:1 n9 cis + trans, C18:0, and C14:0 were the predominant FAs in OM, and OM mostly had higher ∑UFA, including nutritionally desirable FAs; but lower ∑SFA among four regions or in April and August (p < 0.001). The model prepared using stepwise discriminant analysis showed a classification accuracy of 100% for original and cross-validated sample sets. Our results have characterized regional and monthly nutritional variations of OM, thereby potentially suggesting the applicability of a reliable Korean geographical identification labeling system using nutrient compositional analysis of OM.

Comprehensive analysis of the microbial communities and operational parameters of two full-scale anaerobic digestion plants treating food waste in South Korea: Seasonal variation and effect of ammonia.

There are about ninety full-scale anaerobic digestion (AD) plants in South Korea that treat food waste (FW); however, the key diff ;erences in the microbial communities in different seasons and the effects of ammonia in AD remain poorly understood. In this study, the seasonal changes in microbial communities associated with operational parameters of two full-scale ADs (C and W plants) treating FW were analyzed. The organic loading rate (OLR) variability had an influence on the seasonal CH4 yield; the W plant had a lower CH4 yield with an unstable AD performance while the C plant had a higher CH4 yield with a stable AD performance. It was mainly due to the substantially different NH4+ concentration; the W plant had a NH4+ concentration nearly 1.6 times higher compared to the C plant. The high NH4+ presence in the W plant led to the dominance of class Clostridia, and methanogenesis was mostly done by hydrogenotrophs (Methanomassiliicoccus luminyensis). Additionally, the members belonging to Clostridia and Bacteroidia were found at both plants in each season (share ≥0.5%) implying their indispensable role during the anaerobic digestion of FW.