Association between flavor composition and sensory profile in thermally processed mandarin juices by multidimensional gas chromatography and multivariate statistical analysis.

Thermal pasteurization decreases the sensory quality of mandarin juice. Flavor composition was determined in four fresh-squeezed and heat-processed mandarin juice varieties using molecular sensory science approaches. The relationships between odorants and sensory profiles were analyzed, and markers for flavor deterioration were screened by multivariate statistical analysis. Seventy-four volatiles were identified, among which 36 odorants with flavor dilution factors ranging from 2 to 128 were detected by multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) coupled with aroma extract dilution analysis (AEDA). Higher intensities of cooked and off-flavor notes were observed in the heated mandarin juice, which was related to the concentration changes of the methional, methanethiol, dimethyl sulfide, and carbon disulfide by partial least squares (PLS) analysis. Ten potential markers (methional, methanethiol, dimethyl sulfide, hydrogen sulfide, ß-damascenone, camphene, trans-ß-ionone, decanal, d-limonene, and α-pinene) were responsible for the sensory discrimination of fresh-squeezed and heated mandarin juices.

Content analysis and drug safety evaluation of four furanocoumarins in six pomelos produced in China.

The content of 4 6',7'-dihydroxybergamottin (DHB), bergamottin, isoimperatorin and epoxybergamottin of six pomelos produced in China were detected by High-performance liquid chromatography-diode array detection and their safety of related medicines was evaluated by inhibition of medium concentration (IC50) of cytochrome oxidases CYP450-like. The results showed that the total content of the four furanocoumarins in these pomelo juices from high to low in order was Guanximi pomelo > Liangping pomelo > Pinghemi pomelo > grapefruit > Huyou > Shatian pomelo. The concentration of isoimperatorin in grapefruit, DHB, bergamottinand and isoimperatorin in Liangping, bergamottin and epoxybergamottin in Pinghemi and all the four furanocoumarins in Guanximi were exceeded the corresponding IC50; although Huyou and Shatian contained some furanocoumarins, they did not exceed IC50. Therefore, when taking drugs metabolised by CYP450-like enzymes, Guanximi, Liangping, Pinghemi, and grapefruit should be avoided to consume, but it is relatively safe to eat Huyou and Shatian.

Identification of Light-Induced Key Off-Flavors in Ponkan Mandarin Juice Using MDGC-MS/O and GC-MS/PFPD.

Light-induced off-flavor compounds in Ponkan mandarin juice were investigated during its shelf-life by headspace solid-phase microextraction multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) and a GC-MS/pulsed flame photometric detector (GC-MS/PFPD). A total of 34 aroma-active compounds with flavor dilution (FD) factors from 2 to 128 were tentatively identified by aroma extract dilution analysis-MDGC-MS/O. Among them, a light-induced off-flavor compound with a high FD factor, methional (cooked potato), was positively identified in the Ponkan mandarin juice at the end of the shelf-life. In addition, 11 volatile sulfur compounds (VSCs), including 6 screened shelf-markers (variable identification, VID > 0.80), were identified in Ponkan mandarin juice by a sulfur detector (PFPD). Four VSCs exhibited odor activity values exceeding 1. Three VSCs (methanethiol, dimethyl trisulfide, and methional) were confirmed as key light-induced off-flavor compounds in Ponkan mandarin juice based on addition/omission experiments. Furthermore, light irradiation accelerated the degradation of sulfur precursors (methionine and MMS) and the formation of these VSCs leading to an increase in off-flavor intensity.

Effect of Trilobatin from Lithocarpus polystachyus Rehd on Gut Microbiota of Obese Rats Induced by a High-Fat Diet.

Trilobatin was identified as the primary bioactive component in the Lithocarpus polystachyus Rehd (LPR) leaves. This study explored the antiobesity effect of trilobatin from LPR leaves and its influence on gut microbiota in obese rats. Results showed that trilobatin could significantly reduce body and liver weight gain induced by a high-fat diet, and the accumulation of perirenal fat, epididymal fat, and brown fat of SD (Male Sprague-Dawley) obese rats in a dose-independent manner. Short-chain fatty acids (SCFAs) concentrations increased, especially the concentration of butyrate. Trilobatin supplementation could significantly increase the relative abundance of Lactobacillus, Prevotella, CF231, Bacteroides, and Oscillospira, and decrease greatly the abundance of Blautia, Allobaculum, Phascolarctobacterium, and Coprococcus, resulting in an increase of the ratio of Bacteroidetes to Firmicutes (except the genera of Lactobacillus and Oscillospira). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway predicted by the Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) indicated the different relative metabolic pathways after trilobatin supplementation. This study may reveal the contribution of gut microbiota to the antiobesity effect of trilobatin from LPR leaves and predict the potential regulatory mechanism for obesity induced by a high-fat diet.

Methanethiol, an Off-Flavor Produced from the Thermal Treatment of Mandarin Juices: A Study of Citrus Sulfur Volatiles.

The off-flavor produced after thermal stabilization of mandarin (Citrus reticulata, Blanco) juices has limited the production of commercial juices. Methanethiol, a putrid-smelling sulfur volatile, has been identified for the first time in heated mandarin juices. Identification was achieved using a combination of capillary gas chromatography with two dissimilar columns and a dual sulfur-specific pulsed flame photometric detector and selected ion mass spectrometry detection. Static headspace solid-phase microextraction quantitation found that average odor activity values (OAVs) in heated juices were 25.5 for methanethiol compared to 10.8 for dimethyl sulfide. OAVs for methanethiol and dimethyl sulfide in fresh juices were ND (not detected) and 5.5, respectively. Hydrogen sulfide, carbonyl sulfide, carbon disulfide, and dimethyl disulfide were also identified and quantitated. Thermal decomposition studies of nonvolatile sulfur-containing potential precursors indicated that methionine was the major source of methanethiol. Additional heating studies with model juices demonstrated that ascorbic acid greatly accelerated the formation of methanethiol and methional, as well as dimethyl di and tri sulfides.

Weight loss effect of sweet orange essential oil microcapsules on obese SD rats induced by high-fat diet.

Obesity is one of the most common and major health concerns worldwide. Weight management through dietary supplements with natural plant extracts has become the focus of current research. Sweet orange essential oil (SOEO) is a natural plant extract, with many bioactivities. In order to evaluate the weight loss effect of SOEO microcapsules and investigate the underlying mechanism, we fed high-fat diet-induced obese SD rats with SOEO microcapsules for 15 days and found that SOEO microcapsules reduced body weight gain by 41.4%, decreased total cholesterol level, alleviated liver and adipose tissue pathological alteration. The results of fluorescence quantitative PCR revealed that decreasing the expression of peroxisome proliferators-activated receptor-γ, upregulating of uncoupling protein 2, hormone sensitive lipase and carnitine palmitoyltransferase I, inhibiting the expression of acetyl-CoA carboxylase appear to be the mechanism of SOEO microcapsules to lose weight. This study suggests that SOEO microcapsule is a potential dietary supplement for weight loss. Abbreviations: SOEO: sweet orange essential oil; TC: total cholesterol; TG: triglyceride; LDL-c: low-density lipoprotein cholesterol; HDL-c: high-density lipoprotein cholesterol; PPARα: peroxisome proliferators-activated receptor-α; PPARγ: peroxisome proliferators-activated receptor-γ; UCP2: uncoupling protein 2; HSL: hormone sensitive lipase; CPT1: carnitine palmitoyltransferase I; ACC: acetyl-CoA carboxylase; NPY: neuropeptide Y; LEP: leptin; INS: insulin; ALT: alanine aminotransferase; AST: aspartate aminotransferase.

Determination of citrus juice coumarins, furanocoumarins and methoxylated flavones using solid phase extraction and HPLC with photodiode array and fluorescence detection.

A synergistic combination of analytical techniques was developed for the simultaneous determination of the three most biologically active chemical families in citrus juices: methoxylated flavones, coumarins, and furanocoumarins. No rapid methodology has been available to determine them together. A solid phase extraction concentrated these groups and a ternary reverse phase HPLC gradient completely resolved them from other juice components. Two coumarins, isomeranzin and osthole, were identified in a sweet orange (C. sinensis) cultivar, Changyecheng, for the first time. Pummelo juice was characterized by coumarin and furanocoumarin epoxides such as meranzin and epoxybergamottin. No epoxides were observed in the more acidic juices. Added furanocoumarin epoxides hydrolyzed rapidly in the most acidic juices. The ratios of the UV peak areas at 320 nm to the fluorescence emission peaks as well as the ratio of fluorescence emission peaks at 450-400 nm could be used to identify chromatographic peaks.

Microcapsule of sweet orange essential oil changes gut microbiota in diet-induced obese rats.

Obesity is associated with the changes in gut microbiota. The aim of present study was to investigate the effects of sweet orange essential oil (SOEO) microcapsules on body weight and gut microbiota in obese rats induced by high-fat diet. By analyzing the body weight, fat rate and the sequence of cloned microbial small-subunit ribosomal RNA genes (16S rDNA) in rats fecal samples, we found that SOEO microcapsules decreased the body weight and increased the relative abundance of Bifidobacterium (genus-level) in gut microbiota. The analysis of endotoxin content proved that SOEO microcapsules protected gut barrier and decreased gut endotoxin levels by increasing the content of Bifidobacterium, then ameliorated low-grade inflammation, achieving the goal of losing weight. This might be the mechanism of SOEO microcapsules to lose body weight and provided a novel anti-obesity dietary supplement.