The Impact of Different Cooking Methods on the Flavor Profile of Fermented Chinese Spicy Cabbage

Chinese spicy cabbage (CSC) is a common traditional fermented vegetable mainly made of Chinese cabbage. In addition to eating raw, boiling and stir-frying are the most common cooking methods for CSC. To identify the impacts of boiling or stir-frying on the quality of CSC, the physicochemical properties, flavor compounds, and sensory properties of CSC were analyzed. A total of 47 volatile flavor compounds (VFCs) were detected by gas chromatography-mass spectrometry. Sulfide was determined as the main flavor compound of CSC, mainly contributed by cabbage, garlic, and onion odors. The content of sulfide decreased significantly after cooking. Nonanal, geranyl acetate, and linalool were newly generated after boiling with odor activity value (OAV) > 1, and contributed fatty, sweet, fruity, and floral odors to BL-CSC. 1-Octen-3-one, 1-octen-3-ol, octanal, nonanal, and (E)-2-nonenal were newly generated after stir-frying with OAV > 1, and contributed mushroom, fatty, and green odors to SF-CSC. Diallyl trisulfide, nonanal, (E)-β-ionone, β-sesquiphellandrene, and (E)-2-decenal were considered as the potential key aroma compounds (KACs) to distinguish the CSCs after different heat treatment. After cooking, the total titratable acidity of CSC increased and the sensory properties changed significantly. This study provides valuable information and guidance on the sensory and flavor changes of thermal processing fermented vegetables.

Effect of Stir-Frying on Physicochemical and Functional Properties of Oat Protein Isolates

The heat treatment required for the deactivation of enzymes was carried out on crop species such as oats. Stir-frying, a frequently employed method for enzyme inactivation to preserve their desirable shelf life, can result in diminished nutritional value and protein degeneration. The mechanism by which stir-frying affects the oat protein remains largely unknown. Therefore, this study aimed to investigate the physicochemical and functional properties of the extracted oat protein isolates (OPI) at different stir-frying durations (0, 10, 20, and 30 min) at a temperature of 230 °C. The findings of this study demonstrated that stir-frying led to a decrease in the content of amino acids (AA), potentially attributed to the involvement of certain amino acids in the Maillard reaction. As the time of stir-frying increased, the secondary structure of OPI underwent changes: specifically, β-turns transformed into β-sheets. The process of protein denaturation and redistribution of chemical bonds resulted in an increase in the disulfide bond content of OPI, leading to aggregation, large particle size, and reduced digestibility. However, the water retention properties, foaming properties, and emulsification properties of OPI showed improvement. These findings provide valuable insights for the controlled and precise processing of oats and highlight the potential of OPI as a functional food.

Anthraquinone Removal from Cassia obtusifolia Seed Water Extract Using Baking, Stir-Frying, and Adsorption Treatments: Effects on the Chemical Composition, Physicochemical Properties of Polysaccharides, and Antioxidant Activities of the Water Extract

Safety issues of the controversial anthraquinones from Cassia obtusifolia seed water extracts (CWEs) limit its application. This work aimed to remove the anthraquinones of CWEs by baking treatment (BT), stir-frying treatment (ST), and adsorption treatment (AT). Effects of these treatments on the chemical composition, physicochemical properties of polysaccharides, and antioxidant activities of CWEs were analyzed and compared. Results indicated that AT exhibited the best removal effect on the total anthraquinone among the three treatments. After AT, the contents of rhein, emodin, aloe-emodin, and aurantio-obtusin of the CWE were below the limit of detection. In addition, AT increased the contents of neutral sugars in CWEs in comparison to BT and ST. None of the treatments had an obvious influence on the structural characteristics of polysaccharides. However, AT decreased the antioxidant activity of CWEs due to their lower anthraquinone content. In summary, AT was considered as an efficient and simple method to remove anthraquinones, while retaining the features of polysaccharides.

The Impact of Domestic Cooking Methods on Myrosinase Stability, Glucosinolates and Their Hydrolysis Products in Different Cabbage (Brassica oleracea) Accessions

Glucosinolate hydrolysis products are responsible for the health-promoting properties of Brassica vegetables. The impact of domestic cooking on the myrosinase stability, glucosinolates and hydrolysis products in 18 cabbage accession was investigated. Cabbages were steamed, microwaved, and stir-fried before analysis. Cooking significantly affected myrosinase stability and glucosinolate concentrations within and between cabbage morphotypes. Myrosinase was most stable after stir-frying, with up to 65% residual activity. Steaming and microwaving resulted in over 90% loss of myrosinase activity in some accessions. Stir-frying resulted in the greatest decrease in glucosinolate concentration, resulting in up to 70% loss. Steamed cabbages retained the highest glucosinolates after cooking (up to 97%). The profile and abundance of glucosinolate hydrolysis products detected varied across all cooking methods studied. Cooking reduced the amounts of nitriles and epithionitriles formed compared to raw samples. Steaming led to a significant increase in the concentration of beneficial isothiocyanates present in the cabbage and a significantly lower level of nitriles compared to other samples. Microwaving led to a reduction in the concentrations of both nitriles and isothiocyanates when compared to other cooking methods and raw cabbage. The results obtained help provide information on the optimal cooking methods for cabbage, suggesting that steaming may be the best approach to maximising beneficial isothiocyanate production.

Neither low salivary amylase activity, cooling cooked white rice, nor single nucleotide polymorphisms in starch-digesting enzymes reduce glycemic index or starch digestibility: a randomized, crossover trial in healthy adults

BACKGROUND

It was suggested that low salivary-amylase activity (SAA) and cooling or stir-frying cooked starch decreases its digestibility and glycemic index.

OBJECTIVE

We determined the effects of SAA, cooling, and single-nucleotide polymorphisms (SNPs) in the salivary amylase (AMY1), pancreatic amylase (AMY2A, AMY2B), maltase-glucoamylase (MGAM), and sucrase-isomaltase (SI) genes on starch digestibility and glycemic index of cooked polished rice.

METHODS

Healthy subjects [pilot, n = 12; main, n = 20 with low-SAA (<50 U/mL), and n = 20 with high-SAA (>105 U/mL)] consumed test meals containing 25 g (pilot) or 50 g (main) available carbohydrate at a contract research organization using open-label (pilot) or assessor-blinded (main), randomized, crossover, Latin-square designs (trial registration: NCT03667963). Pilot-trial test meals were dextrose, freshly cooked polished rice, cooked rice cooled overnight, stir-fried hot rice, or stir-fried cold rice. Main-trial test meals were dextrose, dextrose plus 10 g lactulose, plain hot rice, or plain cold rice. In both trials, blood glucose was measured fasting and at intervals over 2 h. In the main trial, breath hydrogen was measured fasting and hourly for 6 h to estimate in vivo starch digestibility. Data were analyzed by repeated-measures ANOVA for the main effects of temperature and stir-frying (pilot trial) or the main effects of SAA and temperature (main trial) and their interactions. Effects of 24 single nucleotide polymorphisms (SNPs) were assessed separately. Means were considered to be equivalent if the 95% CI of the differences were within ±20% of the comparator mean for glucose response/glycemic index or ±7% for digestibility.

RESULTS

Pilot: neither temperature nor stir-frying significantly affected glucose incremental AUC (primary endpoint, n = 12). Main: mean ± SEM glycemic index (primary endpoint, n = 40) was equivalent for low-SAA compared with high-SAA (73 ± 3 vs. 75 ± 4) and cold rice compared with hot rice (75 ± 3 vs. 70 ± 3). Estimated starch digestibility (n = 39) was equivalent for low-SAA compared with high-SAA (95% ± 1% vs. 92% ± 1%) and hot rice compared with cold rice (94% ± 1% vs. 93% ± 1%). No meaningful associations were observed between genotypes and starch digestibility or glycemic index for any of the SNPs.

CONCLUSIONS

The results do not support the hypotheses that low-SAA, cooling, and common genetic variations in starch-digesting enzymes affect the glycemic index or in vivo carbohydrate digestibility of cooked polished rice. This trial was registered at clinicaltrials.gov as NCT03667963.

Pharmacokinetic comparisons of six steroid saponins in rat plasma following oral administration of crude and stir-fried Fructus Tribuli extracts by UHPLC-MS/MS

Modern pharmacological studies have shown that Fructus Tribuli can improve sexual function and treat cardiovascular diseases. In this study, we focused on comparing the pharmacokinetics of crude Fructus Tribuli (CFT) and stir-fried Fructus Tribuli (SFT) to further clarify the changes in chemical composition in vivo. The quantitation of six analytes was performed in a triple quadrupole mass spectrometer using the multiple reaction monitoring mode. Separation was performed on a Halo® C₁₈ column using 0.05% formic acid and 5 μmol/L sodium formate in water, and 0.05% formic acid and 5 μmol/L sodium formate in acetonitrile as the mobile phase. The selectivity, precision, accuracy, extraction recovery, matrix effect and stability of the method were fully validated. Compared with the crude group, the parameters C_max and AUC_0-t of terrestroside B and terrestrosin K increased significantly (P < 0.05), but the C_max and AUC_0-t of polianthoside D, terrestrinin D, tribuluside A and terrestrosin D were decreased, terrestrosin D being especially decreased (P < 0.05), after oral administration of SFT extract. These results showed that the developed method was suitable for pharmacokinetic analysis of the six steroid saponins of CFT and SFT in rat plasma, and can be used to facilitate future clinical studies.

Widely Targeted UHPLC-MS/MS Metabolomic Analysis on the Chemical Variation in Blueberry-Filled Pastries During Processing

The majority of components in fruits are sensitive to heat-processing. Nevertheless, fruits are becoming popular ingredients in processed foods, like bakery foods. Therefore, the fate of the components in the fruit-involved food during thermal processing is important for the assessment of their nutritional values and sensory properties. Unfortunately, comprehensive knowledge of the compositional alteration in real food products during processing is limited. In the current study, a popular bakery food, blueberry-filled pastry, was taken as the object, and a widely targeted metabolomic approach was applied to investigate the holistic compositional variation of blueberry filling during pastry preparation. Amongst the total of 630 chemicals identified, 288 chemicals were screened as differential compounds between samples collected at different processing stages. The most variation of the chemicals was observed during the process of stir-frying. A total of 197 chemicals varied significantly in concentrations during stir-frying, while only 75 chemicals altered significantly in contents during baking. Amongst 288 differential compounds, 117 belonged to the group of phenolic compounds, with the others found to be sugars and organic acids, amino acids, lipids, nucleotides, etc. The possible mechanisms of the chemical alterations during thermal processing were also discussed in the current study. The data provide comprehensive information on the compositional changes in berry-containing fillings during thermal processing, and hints and emphasis for further investigation of the underlying mechanisms.

The Potential Transformation Mechanisms of the Marker Components of Schizonepetae Spica and Its Charred Product

Schizonepetae Spica (SS) is commonly used for treating colds, fevers, bloody stool and metrorrhagia in China. To treat colds and fevers, traditional Chinese medicine doctors often use raw SS, while to treat bloody stool and metrorrhagia, they usually use Schizonepetae Spica Carbonisata (SSC; raw SS processed by stir-frying until carbonization). However, there have been limited investigations designed to uncover the mechanism of stir-fry processing. In the present study, a method combining gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) was developed for the comprehensive analysis of the chemical profiles of SS and SSC samples. Principal component analysis of the GC-MS data demonstrated that there were 16 significant differences in volatile compounds between the SS and SSC samples. The simultaneous quantification of six nonvolatile compounds was also established based on HPLC, and remarkable differences were found between the two products. These changes were probably responsible for the various pharmacological effects of SS and SSC as well as the observed hepatotoxicity. Finally, the mechanisms could be rationalized by deducing possible reactions involved in the transformation of these marker components. This work reports a new strategy to reveal the chemical transformation of SS during stir-fry processing.

Study on steroidal saponins in crude and stir-fried Fructus Tribuli by ultra-high-performance liquid chromatography-mass spectrometry coupled with multivariate statistical analysis

Fructus Tribuli is a traditional Chinese medicine used clinically for many years. Crude Fructus Tribuli and stir-fried Fructus Tribuli are recorded in the Pharmacopoeia of the People's Republic of China. However, the differences between steroidal saponins in crude Fructus Tribuli and stir-fried Fructus Tribuli have not been compared. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry along with multivariate statistical analysis was developed to discriminate the chemical profiles and identify the steroidal saponins of crude Fructus Tribuli and stir-fried Fructus Tribuli. Additionally, an ultra-high-performance liquid chromatography triple-quadrupole mass spectrometer was used for the simultaneous quantification of nine major steroidal saponins to analyze the variations between crude Fructus Tribuli and stir-fried Fructus Tribuli. Finally, a total of 30 steroidal saponins whose structures or contents changed significantly after processing were found and identified. The mechanism of structural transformations deduced indicated that during the stir-frying of Fructus Tribuli, C-22 hydroxy furostanol saponins were converted to the corresponding furostanol saponins containing C-20-C-22 double bonds by dehydroxylation and deglycosylation reactions that occurred in the spirostanol saponins causing the generation of steroidal sapogenins. This study was successfully applied to the global analysis of crude Fructus Tribuli and stir-fried Fructus Tribuli. The results of this research will be beneficial to explore the processing mechanism of Fructus Tribuli.

Influence of Cooking Methods on Glucosinolates and Isothiocyanates Content in Novel Cruciferous Foods

Brassica vegetables are of great interest due to their antioxidant and anti-inflammatory activity, being responsible for the glucosinolates (GLS) and their hydroxylated derivatives, the isothiocyanates (ITC). Nevertheless, these compounds are quite unstable when these vegetables are cooked. In order to study this fact, the influence of several common domestic cooking practices on the degradation of GLS and ITC in two novel Brassica spp.: broccolini (Brassica oleracea var italica Group x alboglabra Group) and kale (Brassica oleracea var. sabellica L.) was determined. On one hand, results showed that both varieties were rich in health-promoter compounds, broccolini being a good source of glucoraphanin and sulforaphane (≈79 and 2.5 mg 100 g⁻¹ fresh weight (F.W.), respectively), and kale rich in glucoiberin and iberin (≈12 and 0.8 mg 100 g⁻¹ F.W., respectively). On the other hand, regarding cooking treatments, stir-frying and steaming were suitable techniques to preserve GLS and ITC (≥50% of the uncooked samples), while boiling was deleterious for the retention of these bioactive compounds (20–40% of the uncooked samples). Accordingly, the appropriate cooking method should be considered an important factor to preserve the health-promoting effects in these trending Brassica.

Hydrolysis before Stir-Frying Increases the Isothiocyanate Content of Broccoli

Broccoli is found to be a good source of glucosinolates, which can be hydrolyzed by endogenous myrosinase to obtain chemopreventive isothiocyanates (ITCs); among them, sulforaphane (SF) is the most important agent. Studies have shown that cooking greatly affects the levels of SF and total ITCs in broccoli. However, the stability of these compounds during cooking has been infrequently examined. In this study, we proved that the half-lives of SF and total ITCs during stir-frying were 7.7 and 5.9 min, respectively, while the myrosinase activity decreased by 80% after stir-frying for 3 min; SF and total ITCs were more stable than myrosinase. Thus, the contents of SF and total ITCs decreased during stir-frying largely because myrosinase was destroyed. Subsequently, it was confirmed that compared to direct stir-frying, hydrolysis of glucosinolates in broccoli for 90 min followed by stir-frying increased the SF and total ITC concentration by 2.8 and 2.6 times, respectively. This method provides large quantities of beneficial ITCs even after cooking.

Chemical analysis of raw and processed Fructus arctii by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry

Background:

In traditional Chinese medicine (TCM), raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae), is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii.

Materials and Methods:

To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA) by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry.

Results:

The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials.

Conclusion:

We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM.