美藤果油的研究开发进展

美藤果(Plukenetia volubilis L.)原产于南美洲,已被当地居民食用了3 000多年.美藤果油中α-亚麻酸含量在42％以上,总不饱和脂肪酸约占脂肪含量的92％以上,是一种营养价值很高的健康食用油,目前已被批准为新资源食品.本文介绍了美藤果油在成分、性质、毒理安全性和产品应用方面的研究开发进展,包括脂肪酸和甘三酯组成、脂质活性成分,油脂的理化性质、氧化稳定性和热性质,以及其在保健品、化妆品等领域的应用开发进展,最后对美藤果油未来的研究方向进行了总结和展望.     

Optimisation,characterisation and quantification of phenolic compounds in olive cake

The phenolic compounds in extracts from pressed olive cake were investigated. Free phenolic compounds were extracted from olive cake using methanol. To liberate bound phenolic compounds, the olive cake was subjected to basic and acidic hydrolysis followed by methanol extraction. The individual phenolic compounds and antioxidant activity of the extracts were determined. The highest total phenolic content and antioxidant activity were obtained using methanol extraction for 12 h at 70 °C. The RP-HPLC profiles for full-fat and defatted olive cake showed that protocatechuic acid, hydroxybenzoic acid, sinapic acid, p-coumaric acid, rutin and hesperidin were the predominant free phenolic compounds. Meanwhile, syringic acid, sinapic acid, caffeic acid and protocatechuic acid were the predominant bound phenolic acids. A positive correlation was observed between total phenolic content and antioxidant activity. The results indicated that most of the phenolic compounds in olive products were present in their free forms (75–90% of total phenolic content), while bound phenolic compounds were only a small proportion (10–25%) of total phenolic content.     

Antiproliferative and antioxidant activities of Turkish pomegranate (Punica granatum L.) accessions

The objective of this study was to assess antioxidant and antiproliferative activities of four different Turkish pomegranate varieties (Hatay, Hicaz, Adana and Antalya) using an in vitro HepG2 cancer cell model. All the pomegranate extracts employed in this study significantly diminish the proliferation of HepG2 cells in a dose‐dependent manner. The total phenolic acid, anthocyanin and flavonoid contents for each of the four varieties were determined. The Hatay pomegranate variety had the highest total phenolic acid (337.4 ± 2.34 mg/100 g) and flavonoid (58.42 ± 2.25 mg/100 g) contents of the pomegranates examined. Antioxidant activities of the pomegranates were determined using DPPH and ABTS radical scavenging assays. The lack of correlation between colour index value and antioxidant–antiproliferative activities suggested that phenolic acids and flavonoids are predominant compounds influencing pomegranate's bioactivity rather than anthocyanins. Individual phenolic acids found in Hatay pomegranates were determined, using an HPLC system, as gallic acid being the most predominant phenolic compound.     

Bioactive phenolic compounds and functional properties of dehydrated bean flours

The impact of soaking, cooking, and industrial dehydration on the phenolic profile, antioxidant activity, and functional properties of two bean varieties (Cannellini and Pinta) was investigated. HPLC-PAC and HPLC-MS (ESI) analysis identified phenolic acids (44% and 41% of the total of identified phenolics, respectively) as the main phenolic compounds in raw Cannellini flour and catechins and procyanidins (63%) in raw Pinta flour. As a result of the industrial dehydration, a general reduction of these bioactive compounds and antioxidant activities (ORAC) was observed; however, their levels were still relevant in dehydrated bean flours. The raw and processed flours exhibited low oil holding capacity (1.00-1.15 mL/g), whereas water-holding capacities rose to 3.0-3.8 mL/g. Emulsifying activities and foaming capacities were inhibited during thermal processing. Thus, the significant occurrence of bioactive phenolic compounds, the relevant antioxidant capacities along with the interesting functional properties of dehydrated bean flours make them to be considered functional ingredients for food formulation.     

Effect of simulated gastrointestinal digestion on phenolic composition and antioxidant capacity of cooked cowpea (Vigna unguiculata) varieties

Consumption of diets rich in phenolic compounds has been associated with reduced risk of chronic diseases. The effect of cooking and simulated gastrointestinal digestion on phenolic compounds and antioxidant properties of two cowpea (Vigna unguiculata) types was determined. Phenolic acids, flavan‐3‐ols and flavonols were the main groups of phenolic compounds identified. Cooking and simulated enzyme digestion of the cooked cowpea samples rendered some phenolics less extractable (possibly by promoting binding with other food components) or more extractable (possibly by release of bound forms). Total phenolic contents and radical scavenging properties of the cowpeas were reduced upon cooking, but increased upon simulated enzyme digestion. Cowpea extracts inhibited human LDL oxidation at a concentration of 2 mg mL^?1 possibly due to their phenolic content. Phenolic compounds in cowpea can potentially protect against cardiovascular diseases for which LDL oxidation is a risk factor.     

Antioxidant capacity and major phenolic compounds of spices commonly consumed in China

The antioxidant capacity, total phenolic content, and major phenolic compounds of a total of 19 commonly consumed spices in China were systematically investigated. Ultra performance liquid chromatography (UPLC) coupled with photodiode array detector (PDA) was used to identify and quantify the phenolic compounds in the spice extracts. Galangal exhibited the highest antioxidant capacity, associated with the highest total phenolic content. Furthermore, galangin was identified as the principal phenolic component and the main contributor to the highest antioxidant capacity of galangal. Spices in the family Rutaceae and Lauraceae possessed very high antioxidant capacity and high levels of phenolics. Generally, chlorogenic acid and rutin were identified as the dominant phenolic compounds in the spice extracts. This study might provide useful information not only for human health, but also for screening new economic natural antioxidants that could be used in foods.     

Changes in bioactive compounds and antioxidant activity during convective drying of murta (Ugni molinae T.) berries

Murta (Ugni molinae T.) berries were air‐dried at five temperatures (40, 50, 60, 70 and 80 °C), and the changes in β‐carotene, phenolic acids, total phenolic and flavonoid contents and antioxidant capacities (DPPH and ORAC) were investigated. The berries showed a high content of β‐carotene, which decreased during drying temperature between 40 °C and 80 °C. Free and bound phenolic acids were also determined, showing gallic acid to be the prevalent phenolic acid. Total phenolic and flavonoid contents in the dried berries showed a higher decrease at lower temperature due to longer drying time. The radical‐scavenging activity also showed higher antioxidant activity at higher drying temperatures (70–80 °C) than at lower drying temperatures (40–50 °C). Total phenolic content (TPC) and flavonoids showed good correlation with antioxidant capacity. Murta berries proved to be an excellent source of antioxidants and bioactive compounds and are therefore a potential ingredient for new functional food products.     

Green method for determination of phenolic compounds in mung bean (Vigna radiata L.) based on near‐infrared spectroscopy and chemometrics

Mung bean grains exhibit high level of antioxidant activity due the presence of phenolic compounds. Near‐infrared spectroscopy (NIRS), in conjunction with chemometrics, was used to develop a rapid, nondestructive, chemical free and easy‐to‐use method to determine these compounds in sixty genotypes of mung bean. NIRS calibration curve with high‐performance liquid chromatography (HPLC) as reference method was used to determine phenolic compounds (catechin, chlorogenic acid, caffeic acid, p‐coumaric acid, t‐ferulic acid, vitexin, isovitexin, myricetin, quercetin and kaempferol). It was observed that partial least square regression (PLSR) model in the wavelength range of 1600–2500 nm with standard normal variate (SNV) and linear baseline correction (LBC) as preprocessing techniques can measure phenolic compound accurately (R² > 0.987) with root‐mean‐square error less than 1.82%. This study shows that NIRS along with chemometrics is an accurate method to estimate the phenolic compounds rapidly and nondestructively.     

Antioxidant activity and antimicrobial properties of phenolic extracts from acerola (Malpighia emarginata DC) fruit

The antioxidant activity and antimicrobial property of phenolic extracts from acerola (Malpighia emarginata DC) fruit were assessed. The contribution of ascorbic acid and phenolic compounds in the total antioxidant capacity of the extracts was also evaluated. The extracts showed high total phenolic values and possessed high antioxidant activity as expressed by 2,2′‐diphenylpicrylhydrazyl (DPPH) and oxygen radical absorbance capacity assays (ORAC). The ascorbic acid content ranged from 405 to 1744 mg/100 g of fruit on a fresh weight basis. The antioxidant capacity of the phenolic fractions was in the following order: anthocyanins<phenolic acids<flavonoids. The phenolic fractions contributed 7.1–36.5% of the antioxidant activity expressed by ORAC, whereas the contribution of ascorbic accounted for 18–39% of the total activity. Selected extracts from the flavonoids fraction showed some activity against Staphylococcus aureus.     

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

The 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.     

Degradation kinetics of total phenolic compounds,capsaicinoids and antioxidant activity in red pepper during hot air and infrared drying process

Degradation kinetics of total phenolic compounds, capsaicinoids and antioxidant activity in red pepper during both hot air drying and infrared drying were investigated, as well as the correlation between antioxidant compounds and antioxidant capacity was discussed in current study. The fractional conversion kinetic and first order kinetic models were proved to describe the changes of total phenolic compounds vs. drying time and moisture content, respectively. Degradation of capsaicinoids and antioxidant capacity vs. drying time and moisture content both followed fractional conversion kinetic model. Infrared drying accelerated the degradation rate of total phenolic compounds and capsaicinoids vs. drying time as compared with hot air drying at the same temperature; however, a contrary result was found that infrared drying decreased the degradation rate of both total phenolic compounds and capsaicinoids vs. moisture content. Total phenolic compounds exhibited a stronger relationship with antioxidant capacity of red pepper analysed by multiple linear regression analysis.     

The use of an enzymatic extraction procedure for the enhancement of highland barley (Hordeum vulgare L.) phenolic and antioxidant compounds

A multistep enzymatic extraction method was compared with a conventional chemical extraction process to evaluate the phenolic content and antioxidant activity of highland barley (Z2, Zangqing 25; CHQK, Changheiqingke). The main phenolic compound extracted was (+)‐catechin, followed by ferulic acid, p‐coumaric acid, caffeic acid and chlorogenic acid. The multi‐enzymatic digestion yielded a higher retrieval of (+)‐catechin compared to the conventional chemical extraction procedure (P < 0.05). Compounds obtained from the multi‐enzymatic digestion process exhibited significantly higher (P < 0.05) antioxidant activities determined by oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) when compared to chemical extracts. These results suggest that highland barley subjected to in vitro multi‐enzymatic digestion exhibits a higher phenolic content and antioxidant activity than the chemical extraction, and this multi‐enzymatic digestion coupled with the CAA assay may be a valuable tool to evaluate the antioxidant potential of wholegrains and fruits, as well as vegetables.     

Effect of germination on vitamin C,phenolic compounds and antioxidant activity in flaxseed (Linum usitatissimum L.)

Flaxseed (Linum usitatissimum L.) is well known for its health benefits and chemical composition. This study aimed to evaluate the dynamic changes caused by germination in vitamin C, phenolic compounds and antioxidant activities of flaxseed. It was observed that eight‐day germination of flaxseed sprouts caused increases in phytochemical contents, that is 22.1‐fold increase in vitamin C, 2.67‐fold increase in phenolics and 5.48‐fold increase in flavonoid contents as compare to initial concentration in flaxseeds on dry weight basis. The stimulation was also noted in the three identified phenolic acid ingredients including caffeic acid, p‐coumaric acid and ferulic acid. Similarly, the total PSC and ORAC values of flax sprouts at day 8 increased by 3‐ to 4‐folds compared to nongerminated flaxseeds. It is revealed that comparatively, 8‐day germination of flax sprouts leads to a significant increase in vitamin C, phenolic constituents and total antioxidant activities than those of flaxseeds.     

Effect of agitated bed drying on the retention of phenolic compounds,anthocyanins and antioxidant activity of roselle (Hibiscus sabdariffa L.)

An agitated fluidised bed dryer was employed to dry lixiviated roselle (Hibiscus sabdariffa L.) calyxes. The effects of operational drying variables on the chemical attributes such as the retention of monomeric anthocyanins (MA), phenolic compounds, polymeric colour, antioxidant activity and drying rate were analysed. Drying curves showed only decreasing falling rate period. To determine the kinetic parameters, the drying data were fitted to a Page's model, based on the moisture content ratio vs. the drying time; the k values ranged from 1.58 × 10^?5 to 6.28 × 10^?2 s^?1. The different drying conditions showed significant differences in the chemical parameters. When processing wet feeds, as lixiviated roselle calyxes, the mechanical assisted fluidisation can be considered as an innovative concept.     

Total phenolic content and DPPH radical scavenging activity of lettuce (Lactuca sativa L.) grown in Colorado

Total phenolic content (TPC) and antioxidant capacity of lettuce were evaluated using the Folin-Ciocalteu method and DPPH assay, respectively, on 25 cultivars of lettuce, including leaf, romaine, crisphead, and butterhead types, cultivated over two harvest periods. Leaf lettuce possessed the highest TPC and highest DPPH scavenging ability, followed by romaine, butterhead and Batavia (crisphead subtype). Within a lettuce type, red pigmented lettuce cultivars had higher TPC and antioxidant capacity than did green cultivars grown under the same conditions. In addition, lettuce harvested in July possessed higher TPC and antioxidant capacity than did lettuce harvested in September, suggesting that environmental conditions could influence the phenolic content and antioxidant activity of lettuce. These results suggest that Colorado grown lettuce may serve as potential dietary sources of natural phenolic antioxidants.     

Bioactive compounds,in vitro antioxidant capacity and Maillard reaction products of raw,boiled and fried garlic (Allium sativum L.)

Garlic is used in many dishes but some of its bioactive compounds are lost when exposed to heat. This study evaluated bioactive compounds, antioxidant activity and Maillard reaction products of raw (RG), boiled (BG) and fried garlic (FG). Total phenolic compounds, flavonoids, allicin and phytosterol were quantified as well as dietary fibres and mineral content. Antioxidant activities of RG, BG and FG were evaluated by oxygen radical absorbance capacity (ORAC), oxidation of β‐carotene/linoleic acid and Rancimat methods. The main results were the following: thermal processing of RG decreased both bioactive compounds and antioxidant capacity, boiling was found to be less aggressive than frying, and strong correlations were obtained between total phenolic compounds and the antioxidant assays. However, phytosterol content was higher in FG than in RG and BG and higher temperatures increased the formation of Maillard reaction products. It was concluded that RG and BG should be preferred for human consumption as they present higher antioxidant capacity.     

Total phenolic compounds and antioxidant capacities of major fruits from Ecuador

Seventeen fruits from Ecuador were analysed for total soluble phenolic compounds content and for antioxidant capacity, using three different methods (DPPH, FRAP and ABTS⁺). For the total phenolic content measured by the Folin–Ciocalteu method, three groups, having <100, 200–500 and >1000 mg GAE/100 g FW, were clearly distinguishable. Andean blackberry, capulí cherry peel and banana passion fruit were classified in the third group, with concentrations of 2167, 1494 and 1010 mg of GAE/100 g FW, respectively. Antioxidant capacity analyses revealed the same classes. FRAP and ABTS⁺ gave comparable results and were highly correlated (y = 0.691x + 6.78; r² = 0.908). Spectrophotometric measurements showed that the Andean blackberry and capulí peel but not banana passion fruit contained high levels of anthocyanins (λ_max = 520 nm).     

Phenolic composition and antioxidant activity of white mulberry (Morus alba L.) fruits

Eight major mulberry cultivars [Nakhonratchasima 60 (NS 60), Buriram 60 (BR 60), Chumphon (CP), Wavee (WV), Chaingmai (CM), Pikultong (PT), Kamphaengsaen (KS) and Kamnanchul (KJ)] cultivated in Thailand were assessed for their flavonoid and phenolic acid composition using HPLC and tested for antioxidant potential using 2,2‐diphenyl‐1‐picrylhydrazyl hydrate (DPPH) assay. The total phenolic content (TPC) ranged from 104.78 to 213.53 mg GAE/100 g DW, and total flavonoid content (TFC) ranged from 69.58 to 211.01 mg CE/100 g DW. The major flavonoid compounds in mulberry fruit cultivars were (+)‐catechin (309.26–750.01 mg/100 g DW), procyanidin B1 (62.59–224.41 mg/100 g DW), quercetin (5.36–58.42 mg/100 g DW), rutin (18.73–26.90 mg/100 g DW) and (?)‐epicatechin (8.47–29.21 mg/100 g DW). Gallic acid, cinnamic acid and p‐hydroxybenzoic acid were found to be the major phenolic acids in mulberry fruit cultivars. The gallic acid and cinnamic acid contents ranged from 7.33 to 23.90 mg/100 g DW and from 11.64 to 15.05 mg/100 g DW, respectively. p‐Hydroxybenzoic acid content ranged from 1.77 mg/100 g DW (PT) to 7.13 mg/100 g DW (KJ). DPPH‐scavenging ability was excellent for ethanolic extract of NS 60, and EC₅₀ value of NS 60 (241.83 μg mL^?1) was significantly lower than those of the others (P < 0.05). TPC and TFC of the mulberry fruit were positively correlated with the DPPH‐scavenging ability.