Identifying high-risk factors and mitigation strategies for acrylamide formation in air-fried lotus root chips: Impact of cooking parameters, including temperature, time, presoaking, and seasoning.

This study was conducted to identify high-risk factors and mitigation strategies for acrylamide formation in air-fried lotus root chips by studying the impact of various cooking parameters, including temperature, time, presoaking, and pre-seasoning treatments. The temperature and time had a surprisingly high impact on acrylamide formation. The chips prepared at high temperatures with longer cooking times contained an extremely high acrylamide content, reaching 12,786 ng/g (e.g., 170°C/19 min). A particularly concerning discovery was that the chips with extremely high acrylamide content (up to 17 times higher than the EU benchmark level for potato chips) did not appear overcooked or taste burnt. Higher cooking temperatures required shorter cooking times to properly cook lotus root chips for consumption. A high temperature with a short cooking time (170°C/13 min) greatly benefited acrylamide reduction compared to low temperature with a long cooking time (150°C/19 min). Presoaking in a 0.1% acetic acid solution and pre-seasoning with 1% salt reduced acrylamide levels by 61% and 47%, respectively. However, presoaking in water, vinegar solution, and citric acid solution did not significantly decrease the acrylamide content in the chips. Furthermore, some seasonings significantly increased acrylamide levels (up to 7.4 times higher). For the first time, these findings underscore the high risks associated with air-frying lotus root chips without considering these factors. This study also provides proper air-frying parameters and pretreatment strategies for minimizing acrylamide formation in air-fried lotus chips.

Coordinated Lipid Mobilization during Seed Development and Germination in Peanut (Arachis hypogaea L.).

Peanut (Arachis hypogaea L.) is one of the most important oil crops in the world due to its lipid-rich seeds. Lipid accumulation and degradation play crucial roles in peanut seed maturation and seedling establishment, respectively. Here, we utilized lipidomics and transcriptomics to comprehensively identify lipids and the associated functional genes that are important in the development and germination processes of a large-seed peanut variety. A total of 332 lipids were identified; triacylglycerols (TAGs) and diacylglycerols were the most abundant during seed maturation, constituting 70.43 and 16.11%, respectively, of the total lipids. Significant alterations in lipid profiles were observed throughout seed maturation and germination. Notably, TAG (18:1/18:1/18:2) and (18:1/18:2/18:2) peaked at 23386.63 and 23392.43 nmol/g, respectively, at the final stage of seed development. Levels of hydroxylated TAGs (HO-TAGs) increased significantly during the initial stage of germination. Accumulation patterns revealed an inverse relationship between free fatty acids and TAGs. Lipid degradation was determined to be regulated by diacylglycerol acyltransferase, triacylglycerol lipase, and associated transcription factors, predominantly yielding oleic acid, linoleic acid, and linolenic acid. Collectively, the results of this study provide valuable insights into lipid dynamics during the development and germination of large-seed peanuts, gene resources, and guiding future research into lipid accumulation in an economically important crop.

A highly efficient strategy for simultaneous analysis of eleven monomeric hydroxylated-stilbenes in grape wines and juices by a salting-out assisted liquid-liquid (SALLE) extraction combined with a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

Wine and grape juice are known to have hydroxylated stilbenes, a group of phytoalexins, health-promoting compounds. The determination of stilbene species in wine and grape juices remains a challenging task. Here, we propose an efficient strategy for the simultaneous determination of eleven hydroxylated stilbenes in grape wines and grape juice by a SALLE in conjunction with an HPLC-ESI-MS/MS. SALLE and HPLC-MS/MS conditions were optimized. The proposed method was validated and found to be a simple, sensitive, and reliable measure for the determination of the stilbene species in wine and grape juice. The SALLE was fast and efficient, taking only 10 min. The HPLC-MS/MS was able to quickly separate and quantitate the eleven stilbenes (9 min running). This method was successfully applied to determine the contents of stilbene species in commercial wine and grape juice in Korea. This method is advantageous in reduced sample preparation time, low labor, and cost efficiency.

High impacts of cultivar and home-cooking practice on the content of free myo-inositol, a bioavailable health-promoting cyclitol, in sweet potato.

Free myo-inositol is a bioavailable form of a cyclitol having various health-promoting activities. The impact of cultivar and home-cooking practice on the content of free myo-inositol in sweet potatoes (12 cultivars grown in 2 different locations) was studied. A GC-MS/MS method following in situ trimethylsilylation was established and validated to determine free myo-inositol. The established analytical method was sensitive, precise, and accurate. It was found that free myo-inositol content in sweet potato varied greatly (sevenfolds) with cultivar, ranging from 377.1 to 2628.3 mg/kg dw. A cultivar Poongwon-mi was found to be an exceptionally rich source of free myo-inositol (2628.3 mg/kg dw). Home-cooking practice markedly increased free myo-inositol content (maximum 240%). Baking showed the highest impact on the increase in free myo-inositol, followed by steaming, microwave cooking, and boiling, in decreasing order. This represents the first report of the remarkably high impact of cultivar and home-cooking practice on the free myo-inositol content in sweet potato. PRACTICAL APPLICATION: The free myo-inositol content in sweet potato varied greatly with the cultivars. Poongwon-mi contained a surprisingly high content of free myo-inositol. Home-cooking dramatically increased the free myo-inositol content.

Study on Volatile Profiles, Polycyclic Aromatic Hydrocarbons, and Acrylamide Formed in Welsh Onion (Allium fistulosum L.) Fried in Vegetable Oils at Different Temperatures.

Welsh onion (Allium fistulosum L.) is widely used in diverse Asian cuisines, especially in stir-fried and deep-fried foods. This study investigated the effects of different temperatures (140, 165, and 190 °C) and types of the vegetable frying oil (soybean, corn, canola, and palm oils) on the formation of volatile profiles and hazardous compounds [polycyclic aromatic hydrocarbons (PAHs) and acrylamide] in Welsh onion. Specific volatile chemical groups such as aldehydes, sulfur-containing compounds, and furans/furanones were major volatiles in Welsh onion fried (WOF). The composition of aldehydes and sulfur-containing compounds decreased, while those of furans/furanones increased when WOF samples were exposed to higher temperatures. At 190 °C, PAHs were detected at lower than the EU maximum tolerable limit (the sum of 4 PAHs, <10 µg/kg), and acrylamide was detected below 36.46 µg/kg. The integrated study of both the quality and safety properties can provide fundamental data for the industrial processing of WOF.

An unattended HS-SPME-GC-MS/MS combined with a novel sample preparation strategy for the reliable quantitation of C8 volatiles in mushrooms: A sample preparation strategy to fully control the volatile emission.

Eight carbon (C8) compounds are the key characteristic flavors of mushrooms. The quantitative analysis of the volatiles in mushrooms is challenging especially with the unattended HS-SPME-GC-MS. An unattended HS-SPME-GC-MS/MS in combination with novel sample preparation of the complete control of volatile emissions was developed for the quantitation of the C8 volatiles in mushrooms. The sample preparation strategy was composed of freeze-drying, rehydration, and the addition of a 15% citric acid solution. With this strategy, the volatile emission from mushroom was fully controlled at a certain time point. This method was found to be highly reliable, sensitive, precise, and accurate. This method was successfully applied to measure the contents of the C8 volatiles in the beech, button, and shiitake mushrooms. 1-Octene-3-ol was the most predominant compound in the mushrooms, representing 62.4, 69.0, and 89.2% of the total C8 volatiles in the beech, button, and shiitake mushrooms, respectively.

Fatty Acids and Stable Isotope Ratios in Shiitake Mushrooms (Lentinula edodes) Indicate the Origin of the Cultivation Substrate Used: A Preliminary Case Study in Korea.

Shiitake mushroom (Lentinula edodes) is commonly consumed worldwide and is cultivated in many farms in Korea using Chinese substrates owing to a lack of knowledge on how to prepare sawdust-based substrate blocks (bag cultivation). Consequently, issues related to the origin of the Korean or Chinese substrate used in shiitake mushrooms produced using bag cultivation have been reported. Here, we investigated differences in fatty acids (FAs) and stable isotope ratios (SIRs) in shiitake mushrooms cultivated using Korean and Chinese substrates under similar conditions (strain, temperature, humidity, etc.) and depending on the harvesting cycle. The total FA level decreased significantly by 5.49 mg∙g-1 as the harvesting cycle increased (p < 0.0001); however, no differences were found in FAs between shiitake mushrooms cultivated using Korean and Chinese substrates. Linoleic acid was the most abundant FA, accounting for 77-81% of the total FAs during four harvesting cycles. Moreover, the SIRs differed significantly between the Korean and Chinese substrates, and the harvesting cycles resulted in smaller maximum differences in SIR values compared to those of the cultivation substrate origins. Our findings contribute to the identification of the geographical origin of shiitake mushrooms and may have potential applications in international shiitake-mushroom markets.

Hexane extract of green tea (Camellia sinensis) leaves is an exceptionally rich source of squalene.

Squalene is a cancer chemo-preventive and skin protective agent with high commercial demand. Here, we report for the first time that the green tea (Camellia sinensis) leaves is a surprisingly rich plant-based source of squalene. Young and tender leaves and old and turf leaves were collected at four different collecting seasons (April-August). Lipophilic compounds in the leaves and commercial green teas were extracted with hexane. The squalene contents in the hexane extracts varied greatly with the types of the leaves and collecting seasons. The hexane extract of turf leaves contained significantly higher contents of squalene than the extract of tender leaves. The hexane extract of the turf leaves collected in August contained the highest content of squalene (29.2 g/kg extract). This represents the first report on the qualitative and quantitative information on squalene in green tea leaves.

Characterization of Volatile Profiles of Six Popular Edible Mushrooms Using Headspace-Solid-Phase Microextraction Coupled with Gas Chromatography Combined with Chemometric Analysis.

The classification of six mushroom species (white beech, brown beech, button, oyster, king oyster, and enoki mushrooms) was successfully achieved using canonical discriminant analysis (CDA) on volatile metabolite data sets obtained by headspace-solid-phase microextraction gas chromatography (HS-SPME-GC). Twenty-seven major volatile compounds in six edible mushrooms were positively identified by HS-SPME-GC mass spectroscopy. The total volatile content was highest in brown beech mushroom (P < 0.05). Significant difference in volatile profile was observed between brown beach and white beech mushrooms. Button mushroom contained significantly higher contents of benzaldehyde and benzyl alcohol than the other mushrooms (P < 0.05). Oyster mushroom contained 1-octen-3-ol as the most prevalent volatile, representing 67% out of total volatiles. Hexanal (35.0%) and 1-octen-3-ol (22.5%) were the most abundant volatiles found in king oyster. Hexanal (29.1%) was the most prevalent volatile in enoki mushroom only. Several volatile pairs with very high positive correlation in their levels were identified, representing the highest correlation coefficient (r = 0.970) for the pair of t-2-octenal and 2,4-octandienal. CDA was much more efficient than principal component analysis for the differentiation of mushroom species. PRACTICAL APPLICATION: The present study provided the important information on the volatile metabolite profiles of popular six commercial mushroom species. The present data will be useful for the quality control of mushrooms cultivated in farms and mushroom products processed in food industry. The strategy of canonical discriminant analysis in combination with HS-SPME-GC could be expanded for the determining the authentication of mushroom species.

Analytical features of microwave plasma-atomic emission spectrometry (MP-AES) for the quantitation of manganese (Mn) in wild grape (Vitis coignetiae) red wines: Comparison with inductively coupled plasma-optical emission spectrometry (ICP-OES).

The analytical features of MP-AES for the determination of Mn in wine were studied as compared with ICP-OES. The optimum spectral line (403.076 nm) of MP-AES was different from that (259.373 nm) of ICP-OES. Significant matrix effect was observed with MP-AES, but not with ICP-OES. A simple and cost-effective MP-AES for the quantitation of Mn in wild grape (Vitis coignetiae) red wines were developed and validated. A standard addition method was used to compensate the matrix effects. The sensitivity of MP-AES was comparable to that of ICP-OES. MP-AES was sensitive, precise, accurate and reliable. The Mn concentration in the wild grape wines was in the range of 502-3627 µg L-1. MP-AES had a distinct drawback of low matrix tolerance. However, MP-AES had a clear advantage of the low running cost due to the use of nitrogen gas generated from air with a nitrogen generator.

Inorganic arsenic contents in infant rice powders and infant rice snacks marketed in Korea determined by a highly sensitive gas chromatography-tandem mass spectrometry following derivatization with British Anti-Lewisite.

Toxic inorganic arsenic (iAs) has been reported to be present in high quantity in rice and rice-based products. The inorganic arsenic contents in infant foods (n = 59) of ready-to-cook infant rice powders and infant rice snacks marketed in Korea were determined by a highly sensitive gas chromatography-tandem mass spectrometry (GC-MS/MS). The mean iAs contents in the infant rice powder and infant rice snacks were 65.6 and 54.0 µg/kg, respectively. The percentages of rice powders and rice snack containing iAs over the maximum level (100 µg/kg) set by EU for the infant foods were found to be 21, and 6%, respectively. This result clearly suggested that regulation regarding the maximum limit of iAs levels for the baby rice products is urgently needed to be set in Korea. This represents the first report on the iAs levels in ready-to-cook infant rice powder products and infant snacks marketed in Korea.

Heat-induced conversion of gingerols to shogaols in ginger as affected by heat type (dry or moist heat), sample type (fresh or dried), temperature and time.

The impact of heat type, sample type, temperature and time on the heat-induced conversion of gingerols to shogaols in ginger were studied by an UHPLC-ESI-MS/MS. Heat treatments greatly induced the conversion of gingerols to shogaols in ginger. As the temperature increased, the faster conversion of gingerols into shogaols were observed. However, the efficiency of the heat-induced conversion differed greatly with the heat types. Moist heat treatment induced significantly higher quantity of shogaols than dry heat treatment. The moist heat treatment at 120 °C for 360 min induced the highest conversion, reaching to 2991 mg 6-shogaol per kg ginger. In addition, dry-heat induced conversion was affected by the sample type. The dry-heat treatment on dried powder induced significantly higher quantity of shogaols than that on sliced fresh ginger. This represents the first systematic comparative study on the heat and sample types on the heat-induced conversion of gingerols into shogaols in ginger.

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.

Inorganic arsenic contents in ready-to-eat rice products and various Korean rice determined by a highly sensitive gas chromatography-tandem mass spectrometry.

Rice and rice products have been reported to contain high contents of toxic inorganic arsenic (iAs). The inorganic arsenic contents in microwavable ready-to-eat rice products (n=30) and different types of Korean rice (n=102) were determined by a gas chromatography-tandem mass spectrometry (GC-MS/MS). The method showed low limit of detection (0.015pg), high intra- and inter-day repeatability (<7.3%, RSD), and recovery rates (90-117%). The mean iAs content in the ready-to-eat rice products was 59µgkg-1 (dry weight basis). The mean iAs contents in polished white, brown, black, and waxy rice were 65, 109, 91, and 66µgkg-1, respectively. The percentages of ready-to-eat rice products, white, brown, black, and waxy rice containing iAs over the maximum level (100µgkg-1) set by EU for the infant foods were 17, 4, 70, 36 and 0%, respectively.

Ultra-High-Throughput Analytical Strategy Based on UHPLC-DAD in Combination with Syringe Filtration for the Quantitation of Nine Synthetic Colorants in Beverages: Impacts of Syringe Membrane Types and Sample pH on Recovery.

An ultra-high-throughput approach based on ultra-high-performance liquid chromatography with diode array detection (UHPLC-DAD) in combination with simple syringe filtration was successfully developed and validated for the quantitation of nine synthetic colorants in beverages. The recoveries of the colorants from the beverages were found to be dramatically affected by the syringe filter membrane types and pH of the sample solution. The high recoveries of the nine colorants (92.7-105.9%) were achieved by syringe filtration with poly(vinylidene difluoride) membrane following the pH adjustment of sample solution at pH 7.0. The sample treatment procedure was very simple and took only 1 min. The fast chromatographic separation (1 min) of the nine synthetic colorants was achieved by UHPLC-DAD using a C18-core-shell column. This analytical approach (UHPLC-DAD combined with syringe filtration) took only approximately 3 min. The established method was ultrafast, sensitive, precise, accurate, and reliable. The method was successfully applied to rapidly determine the 9 colorants in 17 beverages.

One step salting-out assisted liquid-liquid extraction followed by UHPLC-ESI-MS/MS for the analysis of isoflavones in soy milk.

We developed and validated a fast UHPLC-ESI-MS/MS in combination with one step salting-out assisted liquid-liquid extraction (SALLE) for high throughput analysis of 12 isoflavones in soy milks. Conventional sample preparation requires two steps composing time-consuming freeze-drying (72h) and solvent extraction (2h). The SALLE required only about 40min, which was over 100times faster without compromising the extraction efficiency. The baseline separation of 12 isoflavones was achieved in 2.5min by the UHPLC-MS/MS which is the fastest chromatographic method ever reported. The new method was fast, simple, selective, sensitive, precise and accurate. The method was successfully applied to 22 commercial soy milks for the high throughput analysis of isoflavones. The new method would be a fast, simple, reliable, and useful measure for the analysis of isoflavones in soy milk especially in the laboratories facing the challenges of saving the analytical time, labor cost and solvent usage.

Simple and Fast Sample Preparation Followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) for the Analysis of 2- and 4-Methylimidazole in Cola and Dark Beer.

We have developed a simple and fast sample preparation technique in combination with a gas chromatography-tandem mass spectrometry (GC-MS/MS) for the quantification of 2-methylimidazole (2-MeI) and 4-methylimidazole (4-MeI) in colas and dark beers. Conventional sample preparation technique for GC-MS requires laborious and time-consuming steps consisting of sample concentration, pH adjustment, ion pair extraction, centrifugation, back-extraction, centrifugation, derivatization, and extraction. Our sample preparation technique consists of only 2 steps (in situ derivation and extraction) which requires less than 3 min. This method provided high linearity, low limit of detection and limit of quantification, high recovery, and high intra- and interday repeatability. It was found that internal standard method with diluted stable isotope (4-MeI-d6 ) and 2-ethylimidazole (2-EI) could not correctly compensate the matrix effects. Thus, standard addition technique was used for the quantification of 2- and 4-MeI. The established method was successfully applied to colas and dark beers for the determination of 2-MeI and 4-MeI. The 4-MeI contents in colas and dark beers ranged from 8 to 319 µg/L and from trace to 417 µg/L, respectively. Small quantity (0 to 8 µg/L) of 2-MeI was found only in dark beers. The contents of 4-MeI (22 µg/L) in colas obtained from fast food restaurants were significantly lower than those (177 µg/L) in canned or bottled colas.

Effects and mechanisms of eugenol, isoeugenol, coniferylaldehyde and dihydroeugenol on the riboflavin-sensitized photooxidation of α-terpinene in methanol.

The effects of eugenol, isoeugenol, coniferylaldehyde, and dihydroeugenol on the riboflavin-sensitized photooxidation of α-terpinene in methanol were studied. Riboflavin greatly accelerated α-terpinene oxidation in methanol during light illumination, resulting in two major oxidation products (p-cymene and ascaridole). The results clearly showed the involvement of Type I and II mechanisms. All the eugenols exerted strong protective activity on riboflavin sensitized photooxidation of α-terpinene. Dihydroeugenol showed the highest protective activity, followed by isoeugenol, coniferylaldehyde, and eugenol, in a decreasing order. Dihydroeugenol greatly inhibited the production of ascaridole, but showed relatively low inhibitory activity on the formation of p-cymene. The protective activity of dihydroeugenol was higher than those of BHA, BHT and sodium azide. Sodium azide, a specific singlet oxygen quencher, showed strong inhibitory activity on the formation of ascaridole, but very low inhibitory activity on the formation of p-cymene, verifying the feasibility of mechanism study with the present model system.

UHPLC-ESI-MS/MS for the Quantification of Eight Major Gingerols and Shogaols in Ginger Products: Effects of Ionization Polarity and Mobile Phase Modifier on the Sensitivity.

We developed and validated an improved ultra high performance liquid chromatography (UHPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) method for the fast separation and quantification of 8 major gingerols and shogaols (4-, 6-, 8-, 10-, and 12-gingerols, and 6-, 8-, and 10-shogaols) in gingerol products. The ionization polarity and mobile phase modifier greatly affected the mass ion profiles and sensitivity of the analytes. A mobile phase modifier of 0.05 mM ammonium formate dramatically decreased the sodium adduct ions and greatly increased the protonated ions of the gingerols and shogaols. Positive ion UHPLC-MS/MS with the ammonium formate in mobile phase showed greatly higher (4.5- to 15.7-fold) sensitivities than negative ion UHPLC. The positive ion UHPLC-MS/MS method showed excellent linearities (r2 > 0.999), low limits of detection (LOD = 2.5 to 8.2 pg), high accuracy and precision, and no considerable matrix effect. Baseline separation of the 8 target compounds was achieved in 1 min by the UHPLC with a short C18 core-shell column. The method was successfully applied to analyze the compounds in fresh and dried powdered gingers, and dietary supplements. The total contents of the major compounds in the fresh gingers, dried powdered gingers, and dietary supplements were in the range of 1114 to 1478, 4380 to 11324, and 2915 to 29998 mg/kg, respectively. There was about 10-fold variation of the content in the dietary supplements with the commercial brands. This represents the 1st report on the ionization polarity and mobile phase modifier on the sensitivity of gingerols and shogaols in LC-mass spectrometry. Furthermore, the established method provided great improvement in chromatographic separation of the target gingerols.

One step derivatization with British Anti-Lewsite in combination with gas chromatography coupled to triple-quadrupole tandem mass spectrometry for the fast and selective analysis of inorganic arsenic in rice.

We developed a new fast and selective analytical method for the determination of inorganic arsenic (iAs) in rice by a gas chromatography - tandem mass spectrometry (GC-MS/MS) in combination with one step derivatization of inorganic arsenic (iAs) with British Anti-Lewsite (BAL). Two step derivatization of iAs with BAL has been previously performed for the GC-MS analysis. In this paper, the quantitative one step derivatization condition was successfully established. The GC-MS/MS was carried out with a short nonpolar capillary column (0.25 mm × 10 m) under the conditions of fast oven temperature ramp rate (4 °C/s) and high linear velocity (108.8 cm/s) of the carrier gas. The established GC-MS/MS method showed an excellent linearity (r(2) > 0.999) in a tested range (0.2-100.0 µg L(-1)), ultra-low limit of detection (LOD, 0.08 pg), and high precision and accuracy. The GC-MS/MS technique showed far greater selectivity (22.5 fold higher signal to noise ratio in rice sample) on iAs than GC-MS method. The gas chromatographic running time was only 2.5 min with the iAs retention time of 1.98 min. The established method was successfully applied to quantify the iAs contents in polished rice. The mean iAs content in the Korean polished rice (n = 27) was 66.1 µg kg(-1) with the range of 37.5-125.0 µg kg(-1). This represents the first report on the GC-tandem mass spectrometry in combination with the one step derivatization with BAL for the iAs speciation in rice. This GC-MS/MS method would be a simple, useful and reliable measure for the iAs analysis in rice in the laboratories in which the expensive and element specific HPLC-ICP-MS is not available.