Analysis of Selected Phenolic Compounds in Organic, Pesticide-Free, Conventional Rice (Oryza sativa L.) Using LC-ESI-MS/MS.

Rice (Oryza sativa L.) contains generous amounts of carbohydrates, proteins, vitamins, and dietary fibers, in addition to secondary metabolites such as phenols and flavonoids that act as antioxidants. The phenolic compounds detected in rice (organic rice (OR), conventional rice (CR), and pesticide-free rice (PFR)), namely, protocatechuic, gentisic, p-hydroxybenzoic, p-coumaric, ferulic, salicylic, and caffeic acids, are notable free radical scavengers. The sum of these phenolic compounds was found to be higher in PFR, followed by CR and OR (p < 0.0001), when the rice types were classified based on the farming system employed. In addition, significant differences were observed in the p-hydroxybenzoic acid levels for the OR and CR groups compared with the PFR groups (p < 0.01). Furthermore, greater quantities of p-coumaric acid were found in CR-08 and OR-02, although these groups contained overall higher and lower sums of phenolic compounds, respectively. Moreover, significance was observed in the sum of the phenolic compounds, although only small quantities were found in polished rice. Further research is thus required to provide a clearer picture regarding the phenolic profiles of different rice brands.

Changes in Soybean (Glycine max L.) Flour Fatty-Acid Content Based on Storage Temperature and Duration.

Soybeans are low in saturated fat and a rich source of protein, dietary fiber, and isoflavone; however, their nutritional shelf life is yet to be established. This study evaluated the change in the stability and quality of fatty acids in raw and roasted soybean flour under different storage temperatures and durations. In both types of soybean flour, the fatty-acid content was the highest in the order of linoleic acid (18-carbon chain with two double bonds; C18:2), oleic acid (C18:1), palmitic acid (C16:0), linolenic acid (18:3), and stearic acid (C18:0), which represented 47%, 26%, 12%, 9%, and 4% of the total fatty-acid content, respectively. The major unsaturated fatty acids of raw soybean flour-oleic acid, linoleic acid, and linolenic acid-decreased by 30.0%, 94.4%, and 97.7%, and 38.0%, 94.8%, and 98.0% when stored in polyethylene and polypropylene film, respectively, after 48 weeks of storage under high-temperature conditions. These values were later increased due to hydrolysis. This study presents the changes in composition and content of two soybean flour types and the changes in quality and stability of fatty acids in response to storage temperature and duration. This study shows the influence of storage conditions and temperature on the nutritional quality which is least affected by packing material.

Characterization of New Polyphenolic Glycosidic Constituents and Evaluation of Cytotoxicity on a Macrophage Cell Line and Allelopathic Activities of Oryza sativa.

Four new constituents, as 5, 7-dihydroxy-4'-methoxyflavonol-3-O-ß-d-arabinopyranosyl-(2''→1''')-O-ß-d-arabinopyrnosyl-2'''-O-3'''', 7''''-dimethylnonan-1''''-oate (1), 5-hydroxy-7, 4'-dimethoxyflavone-5-O-α-d-arabinopyranosyl-(2"→1''')-O-α-d-arabinopyranosyl-2'''-O-3'''', 7''''-dimethylnonan-1''''-oate (2), 5-hydroxy-7, 4'-dimethoxyflavone-5-O-ß-d-arabinofuranosyl-(2"→1''')-O-ß-d-arabinopyranosyl-2'''-O-lanost-5-ene (3) and 4',4''-diferuloxy feruloyl-O-α-d-arabinopyranosyl-(2a→1b)-O-α-d-arabinopyranosyl-(2b→1c)-O-α-d-arabinopyranosyl-(2c→1d)-O-α-d-arabinopyranosyl-(2d→1e)-O-α-d-arabinopyranosyl-2e-3''', 7'''-dimethylnonan-1'''-oate (4), along with three known compounds (5⁻7) were isolated from Oryza sativa leaves and straw. The structures of new and known compounds were elucidated by 1D (¹H and 13C NMR) and 2D NMR spectral methods, viz: COSY, HMBC, and HSQC aided by mass techniques and IR spectroscopy. The cytotoxicity of these constituents was assessed by using (RAW 264.7) mouse macrophage cell line, and allelopathic effects of compounds (1⁻7) on the germination and seedling growth characteristics such as seedling length and root length of barnyardgrass (Echinochloa oryzicola) were evaluated. Significant inhibitory activity was exhibited by compounds comprising flavone derivatives such as (1⁻3) on all of seed germination characteristics. The allelopathic effect of flavone derivatives were more pronounced on seedling length and root length than the germination characteristics. The higher concentration of flavone derivatives showed stronger inhibitory effects, whereas the lower concentrations showed stimulatory effects in some cases.

Study of Quantitative Trait Loci (QTLs) Associated with Allelopathic Trait in Rice.

In rice there are few genetic studies reported for allelopathy traits, which signify the ability of plants to inhibit or stimulate growth of other plants in the environment, by exuding chemicals. QTL analysis for allelopathic traits were conducted with 98 F8 RILs developed from the cross between the high allelopathic parents of 'Sathi' and non-allelopathic parents of 'Nong-an'. The performance of allelopathic traits were evaluated with inhibition rate on root length, shoot length, total length, root weight, shoot weight, and total weight of lettuce as a receiver plant. With 785 polymorphic DNA markers, we constructed a linkage map showing a total of 2489.75 cM genetic length and 3.17 cM of average genetic distance between each adjacent marker. QTL analysis detected on QTL regions on chromosome 8 responsible for the inhibition of shoot length and inhibition of total length. The qISL-8 explained 20.38% of the phenotypic variation for the inhibition on the shoot length. The qITL-8 explained 14.93% of the phenotypic variation for the inhibition on total length. The physical distance of the detected QTL region was 194 Kbp where 31 genes are located.

Fatty Acid- and Amino Acid-Specific Isotope Analysis for Accurate Authentication and Traceability in Organic Milk.

The present study describes compound-specific δ13C and δ15N analyses of fatty acids and amino acids for improving the accurate authentication of organic milk (OM) against conventional milk (CM) collected in Korea. Most δ13Cfatty-acid and δ13Camino-acid values were lower in OM than in CM ( P < 0.05); however, most δ15Namino-acid values displayed weak discriminative power for OM authentication. Higher isotopic fractionation was observed in δ13Cfatty-acid than in δ13Camino-acid and δ15Namino-acid, with fractionation trends differing with individual amino acids. In particular, δ13Clinoleic-acid of -33.5‰ and δ13Cmyristic-acid of -28‰ were determined to be promising year-round threshold values for Korean OM authentication. The δ13Cbulk was highly correlated with δ13CAla ( r = 0.92) and δ13Coleic-acid, trans ( r = 0.77), and strong positive correlations were observed between δ13CVal and δ13CIle ( r = 0.98) and between δ15NThr and δ15NSer ( r = 0.90). Chemometric modeling for OM authentication produced a high quality model ( R2 X = 0.547, R2 Y = 0.865, and Q2 = 0.689) with reliable chemical markers, notably δ13Cmyristic-acid, δ13Clinoleic-acid, and δ13Cstearic-acid. Furthermore, the models developed for seasonal separation in OM ( Q2 = 0.954) and CM ( Q2 = 0.791) were of good quality. Our findings, based on compound-specific isotope data, improve the reliability of OM authentication in cases where bulk stable isotope ratio analysis alone is insufficient. They also provide valuable insight into the control of fraudulent OM labeling in Korea, with potential application in other countries.

Compound-specific δ13C and δ15N analyses of fatty acids and amino acids for discrimination of organic, pesticide-free, and conventional rice (Oryza sativa L.).

Herein, we improve the procedure for organic rice authentication using compound-specific δ13C and δ15N analyses of fatty acids and amino acids, addressing the increasing demand for accurate methods to confirm organic authenticity. Organic rice (OR) and pesticide-free rice (PFR) featured higher values of δ15Nbulk than conventional rice (CR), whereas the corresponding differences between OR and PFR were insignificant. Additionally, OR, PFR, and CR could be discriminated based on some δ13Camino-acid and δ15Namino-acid values. δ13Cbulk was correlated with most δ13Cfatty-acid (r ≥ 0.596) values, and δ15Nbulk was strongly correlated with most δ15Namino-acid (r ≥ 0.834) values. The first component in the orthogonal projection to latent structure-discriminant analysis model allowed for a clear separation between OR and PFR, and good predictability (Q2Y = 0.506). Thus, the present study improves the reliability of organic authentication when bulk stable isotope ratio analysis alone is insufficient for the accurate discrimination of OR, PFR, and CR.

Potential geo-discriminative tools to trace the origins of the dried slices of shiitake (Lentinula edodes) using stable isotope ratios and OPLS-DA.

The Lentinus edodes species, known as shiitake, has a history of extensive use in many cuisines in several East Asian countries owing to its unique and pleasant flavor and texture. As international food trade increases, reliable discrimination of geographical origin is becoming increasingly crucial in Korea to identify cheaper imported Chinese shiitake. Herein, stable isotope ratios (i.e., δ13C, δ15N, δ18O, and δ34S) were measured with a stable isotope ratio mass spectrometer, and a geographical discrimination method using orthogonal projection to latent structure-discriminant analysis was developed. The externally validated discrimination method showed excellent predictability (Q2cum = 0.881) and illustrated that δ18O and δ15N were important isotope markers for the geographical discrimination of dried shiitake slices. This study extends the knowledge of geographical differences between China and Korea evidenced by the shiitake isotope signatures, thereby contributing to potential geographical authentication with broader applications for international shiitake markets.

Regional discrimination of Agaricus bisporus mushroom using the natural stable isotope ratios.

This study was aimed to verify the regional traceability of Agaricus bisporus mushroom using unique δ13C, δ15N, δ18O, and δ34S features combined with chemometric approaches. Ten cultivars from 15 mushroom farms in six regions of Korea were measured their isotopic signatures by stable isotope ratio mass spectrometer. The δ13C, δ15N, δ18O, and δ34S values were significantly different among mushrooms collected from six cultivation regions (P < 0.05). Multi-dimensional plots including the δ15N and δ34S values demonstrated clear regional discrimination of the Saedo and Saehan cultivars produced from Buyeo, Nonsan, Eumseong, Boryeong, or Gyeongju. Partial least-squares discriminate analysis models showed good discrimination for Saedo (Rx2 = 0.798 and Q2 = 0.563) and Saehan (Rx2 = 0.819 and Q2 = 0.894). These preliminary results can extend knowledge of regional isotope signatures in A. bisporus mushroom produced in Korea, contributing to accurate geographical authenticity with potential broader applications for the international mushroom market.

Discrimination of organic milk by stable isotope ratio, vitamin E, and fatty acid profiling combined with multivariate analysis: A case study of monthly and seasonal variation in Korea for 2016-2017.

This study examined the monthly and seasonal variations of δ13C, δ15N, fatty acids (FAs), and vitamin E in organic milk (OM) and conventional milk (CM) collected in Korea during 2016-2017, discriminating OM authenticity with chemometric approaches. Compared to CM, the mean δ13C and δ15N values were lower in OM, whereas the mean α-tocopherol and nutritionally desirable FA contents were higher in OM. Furthermore, δ13C, δ15N, and FA contents vary significantly with the season in OM, whereas α-tocopherol does not show a specific seasonal trend in either OM or CM. Chemometric approaches provided reliable chemical markers, notably C18:3n-3, C18:2n-6, and δ13Cbulk-milk, for accurate OM discrimination according to sampling season. Our findings elucidate milk nutritional quality issues and also provide valuable insight into the control of fraudulent OM labeling in Korea, with potential application in other countries.