Sinapic Acid Content Research Articles

Identification of polyphenol extracts from flaxseed and study on its bacteriostatic mechanism

In this paper, the polyphenol components of flaxseed were identified, and their antibacterial effect and mechanism of action against pathogenic bacteria were studied. Results showed that 14 phenolic acids and 15 flavonoids were identified in flaxseed. Among them, 5 phenolic acids, including ferulic acid, vanillic acid, sinapic acid, gallic acid, 4-hydroxybenzoic acid, as well as 6 flavonoids, including vitexin, quercitrin, quercetin, apigenin, kaempfero1, (+)-dihydroquercetin, were the main phenolic compounds in flaxseed and have been quantitatively analyzed and determined. The content of sinapic acid and quercetin accounted for over 42.67% of flaxseed polyphenol extract. The Oxford Cup method confirmed the antibacterial effect of flaxseed polyphenol extract on Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Salmonella and Pseudomonas fluorescens. The experimental data showed that flaxseed polyphenol extract had a strong inhibitory effect on the growth of both common food-borne pathogens and non-food-borne pathogens. Flaxseed polyphenols increased the permeability of microbial cell membrane, resulting in microbial protein leakage, cell membrane depolarization, and decreased intracellular ATP content, and increased cell membrane potential and cell contents leakage. The results of this study clarified the composition of flaxseed polyphenol and provided a new way for the comprehensive utilization of flaxseed.

Effect of rice bran on properties of yogurt: Comparison between addition of bran before fermentation and after fermentation

Recently, fortifying yogurt with dietary fiber has attracted considerable interest. Since fermentation by lactic acid bacteria might alter the fiber composition and structure, adding fiber into yogurt before and after fermentation might have different effects on properties of yogurt. Therefore, this work investigated effects of adding rice bran before and after fermentation on properties of yogurt to choose a better approach of fortifying yogurt with dietary fiber. Adding rice bran before fermentation significantly decreased syneresis of yogurt at the content of 2.0% and 3.0%, while adding rice bran after fermentation increased syneresis of yogurt. Scanning electron microscopy and confocal laser scanning microscopy analysis indicated that the yogurt gel with rice bran added before fermentation was more compact and porous than the yogurt gel with rice bran added after fermentation. Moreover, the autofluorescence from rice bran added after fermentation was significantly stronger than that in rice bran added before fermentation. Compared with yogurt added with rice bran after fermentation, yogurt added with rice bran before fermentation had higher free p-hydroxybenzoic acid, p-coumaric acid, ferulic acid and sinapic acid contents. These results suggested that fermentation converted bound phenolic acids of rice bran into free ones, which was beneficial to improve the yogurt stability. Thus, the pH, texture and rheological properties of yogurt added with rice bran before fermentation were investigated. It was found that rice bran increased the pH and decreased firmness, consistency, cohesiveness, viscosity and gel strength of yogurt.

Polyphenol and Tryptophan Contents of Purple Corn (Zea mays L.) Variety KND and Butterfly Pea (Clitoria ternatea) Aqueous Extracts: Insights into Phytochemical Profiles with Antioxidant Activities and PCA Analysis.

Plants are a rich source of phytochemical compounds with antioxidant activity. Several studies have revealed that the consumption of plant polyphenols reduces the risk of diseases. Purple corn (Zea mays L. variety KND) and butterfly pea (Clitoria ternatea; CT) were selected to be investigated as alternative natural polyphenol sources to increase the value of these plants. Phytochemical profiles and antioxidant activities of KND cob, silk, husk and CT extracts alone and in combination were investigated in this study. The results revealed that purple corn cob (C) extract had the highest tryptophan, melatonin, total anthocyanin (TAC) and delphinidin content, while the purple corn silk (S) extract showed the highest total phenolic content (TPC) and antioxidant activities. Serotonin was found only in purple corn husk (H) extract and C extract. High contents of tryptophan and sinapic acid were found in CT extract. Principal component analysis (PCA) revealed that strong antioxidant activities were strongly correlated with protocatechuic acid and p-hydroxybenzoic acid contents, moderate antioxidant activities were strongly correlated with melatonin, and low antioxidant activities were strongly correlated with sinapic acid content. Therefore, the purple corn variety KND waste cobs, silk and husks are a potentially rich source of health-promoting phytochemical compounds.

Effects of lactic acid bacteria fermentation on chemical compounds, antioxidant capacities and hypoglycemic properties of pumpkin juice

The purpose of this research was to screen strains to ferment pumpkin juice with excellent flavor and biological activities by the comparison of 5 species of lactic acid bacteria (LAB) strains, namely Lacticaseibacillus casei (Lc), Lactiplantibacillus plantarum (Lp), Lactobacillus acidophilus (La), Lactobacillus helveticus (Lh) and Lacticaseibacillus paracasei (Lpc). The pumpkin juice inoculated with LAB was fermented at 37 °C for 48 h. Viable cell counts were all above 7.92 log CFU/mL, implicating that pumpkin juice was a favorable matrix for LAB. The contents of reducing sugars and total sugars contents obviously declined at the end of fermentation. LAB strains utilized mainly fructose, surcose and glucose for fermentation. Lpc fermented pumpkin juice showed the most abundant organic acid. Furthermore, the strongest DPPH and hydroxyl radical scavenging capacities were observed in Lp, La and Lh, which were positively associated with vanillic acid and sinapic acid contents. There were 30 new volatile compounds that appeared after fermentation, including 8 of ketones and alcohols, 5 esters and so on. The highest sensory scores could be found in La and Lh primarily due to their rich volatile compounds. LAB fermentation was beneficial to inhibiting α-glucosidase and α-amylase activities. In conclusion, La and Lh were more suitable to develop into a functional beverage with pleasant flavor.

The Implications of Composite Dark Purple Rice Malt on Phenolic Acid Profiles, 4-Vinyl Guaiacol Reduction and Enhancing the Antioxidation of Beer

This study highlights the dynamics of phenolic acids, antioxidation, and 4-vinylguaiacol in beer produced with dark purple rice malt, also known as Riceberry rice malt, as an adjunct and base malt. Riceberry rice malt substituted barley malt at 40% (w/w), 60% (w/w), 80% (w/w), and 100% (w/w) with 100% (w/w) barley malt as the control. Two types of ale beer were produced with two yeasts, designated as POF− and POF+. The wort produced with the Riceberry rice malt had higher anthocyanin and vanillic acids relative to all barley malt wort. Fermentation and beer maturation reduced phenolic acids and antioxidant activity in all treatment. Nevertheless, beer produced from 40% (w/w)–80% (w/w) Riceberry rice malt maintained higher p-coumaric acid, vanillic acid, anthocyanin, and antioxidant activity in beers with lower 4-vinylguaiacol relative to all barley malt beer, which also had higher ferulic acid and sinapic acid contents. The beers made from POF+ yeast contained more 4-vinylguaiacol contents than those found in beers made from POF− yeasts. This study suggests that Riceberry rice malt or POF− yeast are suitable raw materials for phenolic acid off-flavour reduction and the stabilisation of antioxidant activity in beer.

Grafting-enhanced tolerance of cucumber to toxic stress is associated with regulation of phenolic and other aromatic acids metabolism.

Toxic stress caused by autotoxins is a common phenomenon for cucumber under monoculture condition. A previous study demonstrated that grafting could enhance the resistance of cucumber to cinnamic acid (CA) stress, but the underlying mechanism behind this enhanced resistance is still unclear. In the present study, we reconfirmed the stronger resistance of grafted rootstock (RG) compared to the non-grafted (NG) cucumber as measured though plant biomass accumulation. In addition, we focused on the phenolic and other aromatic acids metabolism in hydroponic culture model system using a combination of qRT-PCR (to measure gene expression of relevant genes) and HPLC (to detect the presence of phenolic and other aromatic acids). The results showed that the exogenous CA lead to the expression of four enzymes involved in phenolic and other aromatic acids biosynthesis, and a larger increase was observed in grafted rootstock (RG). Specifically, expression of six genes, involved in phenolic and other aromatic acids biosynthesis (PAL, PAL1, C4H, 4CL1, 4CL2 and COMT), with the exception of 4CL2, were significantly up-regulated in RG but down-regulated in NG when exposed to CA. Furthermore, six kinds of phenolic and other aromatic acids were detected in leaves and roots of NG and RG cucumber, while only benzoic acid and cinnamic acid were detected in root exudate of all samples. The CA treatment resulted in an increase of p-hydroxybenzonic acid, benzoic acid and cinnamic acid contents in RG cucumber, but decrease of p-coumaric acid and sinapic acid contents in NG cucumber. Surprisingly, the type and amount of phenolic and other aromatic acids in root exudate was improved by exogenous CA, particularly for RG cucumber. These results suggest that a possible mechanism for the stronger resistance to CA of RG than NG cucumber could involve the up-regulation of key genes involved in phenolic and other aromatic acids metabolism, and that the excessive phenolic compounds released to surroundings is a result of the accumulation of phenolic compounds in a short time by the plant under stress.

Comparison of superior bred strawberry genotypes with popular cultivars in terms of fruit bioactive compounds over the full range of harvest dates

Secondary compounds of fruit are among the essential concerns due to their positive effects on human health. Many studies have attempted to improve these compounds by applying different genotype or cultivation practices such as irrigation and fertilization. This study aimed to find out the effect of different harvest dates on strawberry genotypes in terms of total phenolic (TP), total antioxidant activity (TAA), total monomeric anthocyanin (TMA), and some crucial individual phenolic compounds during the five-month growing season (January - May periods) with one month intervals. Besides, superior bred lines ('33′, '36′ and '61′) were compared with widely grown cultivars ('Rubygem', 'Festival' and 'Fortuna') under the Mediterranean climate conditions. Regarding the genotypes, it was observed that TMA, TP, TAA, (−) epicatechin, (−) epicatechin gallate, pelargonidin 3- glucoside (P3G), and pelargonidin 3- rutinoside (P3R) values were the highest values in the 33-bred line, while the 36-bred line stood out in terms of ferulic acid and cyanidin 3- glucoside (C3G). This study also has shown that the chlorogenic acid and sinapic acid contents of the 61-bred line were found in the highest level compared with the others. Regarding the harvest date, fruit antioxidant activity, total phenolic compounds, and individual phenols such as gallic, syringic, ferulic, (−) epicatechin and ellagic acid were measured the highest in May-harvested fruits, whereas these values were observed at the lowest level in March, except for syringic and (−) epicatechin. On the other hand, rutin, quercetin, sinapic acid, chlorogenic and caffeic acids, and P3G and P3R levels of fruits were the highest in April, when it was the most intense harvest period in Mediterranean climate conditions. These observations indicated that these compounds could be increased by choosing the right genotype and suitable environmental conditions.

Sinapic acid impacts the emulsifying properties of rapeseed proteins at acidic pH

Extensive purification of plant proteins is probably not a prerequisite for their emulsifying properties, however, details of the interfacial stabilization mechanism of less purified protein extracts are not sufficiently known. Phenolic compounds present in less purified plant protein extracts can interact with proteins, inducing protein aggregation, impeding their interfacial properties. Here, we show that when a rapeseed protein mixture (RPM) containing 40 wt% proteins and 6 wt% sinapic acid is used to form oil-in-water emulsions (10.0 wt% oil) at pH 3.8 and at different protein concentrations (0.2–1.5 wt%), emulsion droplets of 2.0–0.6 μm are formed and large protein aggregates are randomly attached to the droplet interface. By reducing the sinapic acid content to 2.5 wt% to produce a rapeseed protein concentrate (RPC) (65 wt% proteins), smaller emulsion droplets are formed (0.4–0.5 μm) at the same protein concentrations, and no large proteins aggregates are present at the droplet interface. According to our findings, in both RPM- and RPC-stabilized emulsions, napins primarily adsorb at the interface, while cruciferins form a secondary layer which protects the droplets against coalescence during homogenization. However, in RPM, the higher sinapic acid content possibly induces aggregation of cruciferins, which hinders the formation of a sufficient secondary layer. As a result, during homogenization, the colliding droplets coalesce, resulting in emulsions with larger droplets. Our findings show that sinapic acid affects the emulsification mechanism of rapeseed proteins at acidic pH, and recommend that plant protein purification might be necessary for the application of plant proteins in emulsion food products.

Pineapple fruits from transgenic plants have limited differences on mesocarp biochemical component contents

Variations brought about by pineapple genetic transformation do not appear to be physiologically significant in fruits In terms of tropical fruit production, pineapple ranks as one of the major commercially grown fruit crops globally. Our previous research led to the development of a technique suitable for genetic modification of pineapple. The transgenic plants generated were characterized following hardening-off and during the subsequent 8 years of in-situ growth. The current work focuses on the results of a comparison of selected fruit mesocarp physical and biochemical (indicators related to oxidative metabolism) traits across untransformed control plants propagated by cutting, micropropagated untransformed control plants, and micropropagated genetically transformed plants. At the fruit ripening stage, the statistical analysis revealed no biologically meaningful differences in fruit mass (with tops included) (c. 2.0 kg) between transgenic and both groups of control plants. Moreover, contents of aldehydes, soluble phenolics, shikimic acid, phenylalanine, tyrosine, and p-coumaric acid were statistically comparable across the three groups. However, there were small but significant differences in the content of chlorophylls (a, b), carotenoids, malondialdehyde, proteins, 1,1-diphenyl-2-picrylhydrazyl, and cell wall-linked phenolics. This also included small changes in the levels of enzymes (i.e. superoxide dismutase and peroxidase). Furthermore, fruits from micropropagated control plants showed 2.2-fold more catalase activity than control plants propagated by cutting and transgenic plants; transgenic fruits contained 1.8-fold more caffeic acid than those from macropropagated and micropropagated control plants; fruits from micropropagated control plants and transgenic plants showed 3.9-folds higher ferulic acid content than macropropagated control plants; fruit sinapic acid content was 2.5-fold higher in micropropagated control plants than in transgenic and macropropagated control plants. The differences in biochemical traits brought about by transformation do not appear to be physiologically significant, given that the fruit mass was not different from control plants.

Gastrointestinal and colonic in vitro bioaccessibility of γ-aminobutiric acid (GABA) and phenolic compounds from novel fermented sorghum food

Effect of lactic acid bacteria fermentation on γ-aminobutiric acid (GABA) and phenolic compounds during the development of red and white sorghum fermented products (RS and WS, respectively) with malted sorghum flour added to each formulation was evaluated. Moreover, intestinal and colonic bioaccessibility of bioactive compounds (IB and CB, respectively) were estimated. Lactic acid fermentation increased significantly (p < 0.05) GABA content in RS and WS (20 and 30%, respectively). Intestinal bioaccessibility of GABA was ~30% for both products. Lactic acid fermentation modified the phenolic acid content differently in the two products. In RS, the free form of ρ-coumaric acid increased, while caffeic, ferulic, and sinapic acid contents decreased. However, WS experienced an increase in the contents of the free ρ-coumaric and sinapic acids. The range of phenolic compound IB and CB was from 1.2 to 54.9%, depending on the product and phenolic acid evaluated. Gallic acid was the most dialyzed phenolic acid at intestinal and colonic levels. The total IB and CB of phenolic compounds was 21 and 6% for RS, and 28% and 4% for WS, respectively.

Influence of biostimulants on phenolic content in broccoli heads directly after harvest and after storage

AbstractBiostimulants are commonly used in horticulture, primarily to increase yield quantity and quality, as well as plant tolerance to stress. The purpose of the study was to determine the effect of amino acid-based biostimulants and amino acids in combination with Ascophyllum nodosum filtrate, applied during the growing season on the phenolic content in broccoli heads both after harvest and after long storage in a cold store. The seedlings were planted in mid-July, and heads were harvested from September to October in each year of the study. Ascophyllum nodosum filtrate at a concentration of 1% was used during seedling production. The plants were watered with biostimulants twice, in the fourth and fifth week after sowing. They were also sprayed with amino acid-based biostimulants (1.5 dm3 ha-1) three times, i.e. after the second, fourth and sixth week after planting. The biostimulants were not used in the control treatment. After harvest, the heads were stored for three weeks in a cold store at 1-2°C and 95% RH. Chemical analyses of total phenolic, caffeic, ferulic and sinapic acids, and of quercetin and kaempferol were carried out on samples of fresh broccoli and after the first, second and third week of storage. It was found that the application of biostimulants resulted in a significant increase in the total phenolic content, sinapic acid content, as well as quercetin content. Both in the control treatment and in the plants treated with the biostimulants, the concentration of all the tested phenolic compounds increased with the duration of storage.

Phenolic acid composition, antioxidant and antimicrobial activities of green gram (vigna radiata) exudate, husk, and germinated seed of different stages

Germinated green gram seeds are widely consumed in the world. During germination, significant volume of exudate is wasted. Total polyphenol, flavonoid and anthocyanin contents in exudate were 80.8 mg GAE/g, 52.42 mg CAE/g and 15.23 mg/g (dw), respectively. In exudate, sinapic acid content was the highest followed by ferulic and gallic acids. Similarly, polyphenol and flavonoid contents in germinated seeds increased, while in husk, it decreased significantly with the germination period, however, anthocyanin content decreased significantly in both. During germination, contents of tannic and gallic acids decreased, while contents of ferulic and sinapic acids increased in both seed and husk. Exudate exhibited potential antioxidant and antibacterial activities. First day germinated seed and husk had the highest antioxidant and antibacterial potential. Thus, exudate and germinated seed extracts can be used as nutraceuticals and used in functional foods. This is the first report on antioxidant and antibacterial properties of green gram exudate. Practical applications Germinated seeds are rich in nutrients and nutraceuitcals. Food industry produces significant amount of germinated green gram and these germinated seeds are consumed as raw as well as after mild processing. After germination, large quantities of liquid as well as husk are obtained. As germinating seeds produce antimicrobial compounds to protect the seedlings, during germination these compounds may leach into exudate. In the present study, we found that green gram exudate and the germinating seed husks possess stronger antioxidant and antibacterial activity against food borne bacteria compared to raw seed. The results suggest that the exudate can be a good source of natural preservatives in food products and it may be an alternative to the use of chemical additives in the food industry.

Identification and allelochemical activity of phenolic compounds in extracts from the dominant plant species established in clear-cuts of Scots pine stands

Abstract: Dominant plant species established in the understory of clear-cuts may have a strong biochemical influence on pine regeneration process, with important consequences for reforestation management. We evaluated and compared the total phenolic content and the allelopathic activity of acqueous extracts from both roots and shoots of dominant plant species established in 1-yr-old and 2-yr-old clear-cuts of Scots pine (Pinus sylvestris L.) stands in Lituania. The highest total content of phenolic compounds was detected in the lingonberry (Vaccinium vitis-idaea L.) shoots from 1-yr-old and 2-yr-old clear-cuts, as well as in the common heather (Calluna vulgaris [L.[ Hull) shoots from 1-yr-old clear-cuts. High-performance liquid chromatography (HPLC) was used to identify and quantify the allelochemicals present in the active fraction to determine their possible role in allelopathy. The highest variety and content of phenolic compounds were observed in shoot extracts of the dominant species from both 1-yr-old and 2-yr-old clear-cuts. Scots pine seed germination and seedling growth were significantly and negatively correlated with ρ-coumaric acid and sinapic acid content, while Scots pine seedling growth was significantly and negatively correlated with ferulic, caffeic and hydroxycinnamic acids contents. The highest contents of these phenolic acids were determined in aqueous extracts of C. vulgaris from 1-yr-old clear-cuts and Rumex acetosella L. of 2-yr-old clear-cuts, which exerted a strong phytotoxicity on Scots pine seed germination. Moreover, morphometric parameters of Scots pine seedlings were most sensitive to aqueous extracts of V. vitis-idaea shoots from both 1-yr-old and 2-yr-old clear-cuts and R. acetosella shoots from 2-yr-old clear-cuts.

Effects of different osmo‐dehydrofreezing treatments on the volatile compounds, phenolic compounds and physicochemical properties in mango (Mangifera indica L.)

SummaryThe influences of different osmotic solution pretreatments (sucrose, glucose and maltose with concentration of 45%) on the volatile compounds, phenolic compounds and other physicochemical parameters in frozen mangoes were studied. Volatile and phenolic compounds were measured using SPME/GC‐MS and HPLC method, respectively. The results revealed that compared with untreated frozen mango, some volatile compounds (e.g. alcohols, aldehydes and some terpenes and esters) increased significantly and there were more compounds identified in osmo‐dehydrofrozen samples. These changes positively affected mango aroma and resulted in higher sensory scores for osmo‐dehydrofrozen samples. In addition, data on phenolic compounds showed that dehydrofrozen samples pretreated in glucose and sucrose had higher ρ‐hydroxybenzoic acid and quercetin contents, respectively, while samples pretreated in maltose showed higher ρ‐coumaric acid and sinapic acid contents compared with untreated frozen samples. The current work indicates that osmo‐dehydrofreezing can improve the retention of phenolic and aromatic compounds in frozen mango.

Zmiany składu fenoli i tokoferoli w różach brokułu w trakcie krótkotrwałego przechowywania

Broccoli (Brassica oleracea L. var. italica) contains numerous biologically active compounds. However, their levels change during processing and storage. The objective of the research study was to determine the effect of short-term storage (1 ÷ 4 days) of broccoli heads at different temperatures (3 oC, 16 oC, and 21 oC) on the contents of phenolic acids, selected flavonoids (quercetin and kaempferol), and tocopherols. Broccoli heads were harvested in autumn when they reached their maximum size and their buds were 2 mm in diameter. The content of phenolics and tocopherols depended on the storage time of broccoli heads. The lowest content of phenolics was found immediately after the broccoli was harvested, whereas the highest content thereof was reported after 4 days of storage. However, the storage temperature did not impact the contents of those compounds. In the research study, the content of caffeic acid was reported to be highest in the fresh broccoli heads; the content of sinapic acid was the second-highest, and that of the ferulic acid was the third-highest. The content of kaempferol in the broccoli heads was higher than that of quercetin. No differences were reported in the content of quercetin and kaempferol at particular storage temperatures on every single day of the experiment. An increase was reported only when compared with the control sample (the 0 day of storage). In the broccoli heads, the predominant tocopherol was α-tocopherol. The lowest loss in the total tocopherols occurred while storing at a temperature of 3 oC and the highest: at a temperature of 21 oC.

Intestinal anti-inflammatory activity of the seeds of Raphanus sativus L. in experimental ulcerative colitis models

Ethnopharmacological relevanceWater extract of Raphanus sativus L. (RSL) seeds was traditionally used to treat digestive inflammatory complaints in Korean culture. RSL seeds exerted antioxidant, anti-inflammatory, and anti-septic functions, suggesting their pharmacological potential for the treatment of inflammatory pathologies associated with oxidative stress such as inflammatory bowel disease. Aim of this studyWe evaluated the intestinal anti-inflammatory effects of RSL seed water extract (RWE) in experimental rat models of trinitrobenzenesulphonic acid (TNBS)- or dextran sodium sulfate (DSS)-induced colitis. Materials and methodsRWE was characterized by determining the content of sinapic acid as a reference material and then assayed in the DSS and TNBS models of rat colitis. Male Sprague–Dawley rats were divided into 10 groups (n=7/group): non-colitic control, DSS or TNBS control, DSS colitis groups treated with RWE (100mg/kg) or mesalazine (25mg/kg), and TNBS colitis groups treated with various doses (10, 40, 70, and 100mg/kg) of RWE or mesalazine (25mg/kg). RWE or mesalazine treatment started the same day of colitis induction and rats were sacrificed 24h after the last treatment followed by histological and biochemical analyses. ResultsOral administration with RWE suppressed intestinal inflammatory damages in both DSS- and TNBS-induced colitic rats. The treatment with 100mg/kg RWE recovered intestinal damages caused by TNBS or DSS to levels similar to that of mesalazine, decreasing the activity of myeloperoxidase activity and the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1β. RWE treatment inhibited malondialdehyde production and glutathione reduction in colon of colitis rats. The administration of RWE at dose of 100mg/kg also suppressed the TNBS- or DSS-stimulated expression of TNF-α, IL-1β, monocyte chemotactic protein-1, inducible nitric oxide, and intercellular adhesion molecule-1. Furthermore, RWE inhibited p38 kinase and DNA–nuclear factor-κB binding activities, both of which were stimulated in the colitic rats. ConclusionsThe current findings show that RWE ameliorates intestinal oxidative and inflammatory damages in DSS and TNBS models of rat colitis, suggesting its beneficial use for the treatment of intestinal inflammatory disorders.

Antioxidant capacities and polyphenolics of Chinese cabbage (Brassica rapa L. ssp. Pekinensis) leaves

Chinese cabbage (Brassica rapa L. ssp. Pekinensis) is a green leafy vegetable used mainly in kimchi, salted and fermented dishes. Consumer preference for the leaf portion differs according to the type of dishes. In this study, Chinese cabbage was divided into three parts, and their antioxidant activities were investigated through in vitro assays. The total phenolic contents (TPC), total flavonoid contents (TFC), and vitamin C contents were also determined as indicators of antioxidant contents. The phenolic acids and flavonoids were separated and identified using high performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). The outer leaf had the strongest antioxidant activity with the maximum antioxidant contents, followed by the mid- and inner leaves. Principal component analysis (PCA) revealed that outer leaf is positively related to caffeic acid, p-coumaric acid, ferulic acid, and myricetin contents, whereas the mid- and inner leaves are negatively related to sinapic acid contents.

A novel integrated downstream processing approach to recover sinapic acid, phytic acid and proteins from rapeseed meal

AbstractBACKGROUNDCurrently, several techniques exist for the downstream processing of protein, phytic acid and sinapic acid from rapeseed and rapeseed meal, but no technique has been developed to separate all of the components in one process. In this work, two new downstream processing strategies focusing on recovering sinapic acid, phytic acid and protein from rapeseed meal were established.RESULTSThe sinapic acid content was enhanced by a factor of 4.5 with one method and 5.1 with the other. The isolation of sinapic acid was accomplished using a zeolite‐based adsorbent with high adsorptive and optimal desorption characteristics. Phytic acid was isolated using the anion‐exchange resin Purolite A200®. In addition, the processes resulted in two separated protein fractions. The ratios of globulin and albumin ratio to the total protein were 59.2% and 40.1%, respectively. The steps were then combined in two different ways: (a) a ‘sequential process’ using the zeolite and A200 in batch processes; and (b) a ‘parallel process’ using only A200 in a chromatographic system to separate all of the compounds.CONCLUSIONSIt can be concluded that isolation of all three components was possible in both processes. These could enhance the added value of current processes using rapeseed meal as a protein source. © 2015 Society of Chemical Industry

Endogenous Phenolics in Hulls and Cotyledons of Mustard and Canola: A Comparative Study on Its Sinapates and Antioxidant Capacity

Endogenous sinapic acid (SA), sinapine (SP), sinapoyl glucose (SG) and canolol (CAN) of canola and mustard seeds are the potent antioxidants in various lipid-containing systems. The study investigated these phenolic antioxidants using different fractions of canola and mustard seeds. Phenolic compounds were extracted from whole seeds and their fractions: hulls and cotyledons, using 70% methanol by the ultrasonication method and quantified using HPLC-DAD. The major phenolics from both hulls and cotyledons extracts were SP, with small amounts of SG, and SA with a significant difference of phenolic contents between the two seed fractions. Cotyledons showed relatively high content of SP, SA, SG and total phenolics in comparison to hulls (p < 0.001). The concentration of SP in different fractions ranged from 1.15 ± 0.07 to 12.20 ± 1.16 mg/g and followed a decreasing trend- canola cotyledons > mustard cotyledons > mustard seeds > canola seeds > mustard hulls > canola hulls. UPLC-tandem Mass Spectrometry confirmed the presence of sinapates and its fragmentation in these extracts. Further, a high degree of correlation (r = 0.93) was noted between DPPH scavenging activity and total phenolic content.

Influence of Microwaves Treatment of Rapeseed on Phenolic Compounds and Canolol Content

Rapeseeds were treated with microwaves under 800 W for 0, 1, 2, 3, 4, 5, 6, 7, and 8 min at a frequency of 2450 MHz, and oil was extracted with a press to investigate the influence on phenolic compounds, including sinapine, the main free phenolic acids, and canolol content in the rapeseeds and oil from them. The results indicated that sinapine and sinapic acid was the main phenolic compound and free phenolic acid in the rapeseed, respectively, and canolol was the main phenolic compound in the oil from rapeseed by cold press. Microwave treatment significantly influenced phenolic compounds content in the rapeseeds and oil from them. The sinapine, sinapic acid, and canolol content in rapeseed first increased and then decreased depending on the period of microwave radiation (p < 0.05). The canolol content of 7 min microwave pretreatment rapeseed increased to the maximum and was approximately six times greater than that of the unroasted rapeseed. The amount of canolol formed was significantly correlated with the content of sinapic acid and sinapine (for sinapic acid, r = -0.950, p < 0.001, for sinapine, r = -0.828, p < 0.05) and also the loss of sinapic acid and sinapine (for sinapic acid, r = 0.997, p < 0.001, for sinapine, r = 0.952, p < 0.05) during roasting. There were differences in the transfer rate of difference phenolic compounds to the oil extracted by press. Almost all of the sinapine remained in the cold-pressed cake and only 1.4-2.7% of the sinapic acid, whereas approximately 56-83% of the canolol was transferred to the oil. The transfer ratio of canolol significantly increased with microwave radiation time (p < 0.001). Microwave pretreatment of rapeseed benefited improving the oxidative stability of oil.