ANTIOXIDANT ACTIVITY OF PHENOLIC FRACTIONS OF EVERLASTING PEA, FABA BEAN AND BROAD BEAN

Extracts of seeds of everlasting pea, faba bean and broad bean were prepared using 80% acetone. Five fractions were separated from each extract on a Sephadex LH-20 column using methanol as the eluate. The antioxidant activity of fractions was investigated in a β-carotene-linoleate model system. For individual fractions, UV spectra were recorded and the content of total phenolics determined. Fractions were also characterized based on the number of phenolic compounds, and their antioxidant activity determined by TLC analysis. Results of β-carotene-linoleate model systems indicated that antioxidant activities of separated fractions were in the order of everlasting pea > faba bean > broad bean. Individual fractions contained several phenolic compounds as noted by TLC. Absorption maxima from UV spectra showed that flavonoids, and not phenolic acids, were the main phenolic compounds in separated fractions. Spots on the plates sprayed with a solution of β-carotene and linoleic acid indicated that many of these compounds can act as natural antioxidants.     

ANTIOXIDANT ACTIVITY OF PHENOLIC EXTRACTS OF EVENING PRIMROSE (OENOTHERA BIENNIS): A PRELIMINARY STUDY

Phenolic compounds from ethanolic extracts of evening primrose ( Oenothera biennis ) were separated into ten fractions using Sephadex LH-20 column chromatography. For individual fractions, UV spectra were recorded and the content of total phenolics determined. Antioxidant activity of each isolated fraction was examined in a β-carotene-linoleate model system. Fractions were further characterized for the number of phenolic compounds, presence of proanthocyanidins and their antioxidant activity by TLC analysis. Strong antioxidant properties were noted for fractions with high content of total phenolics (fractions IV-X). Vanillin-positive compounds were observed in fractions VI-X and one compound was tentatively identified as (+)catechin/(−)epicatechin. From fraction IV, two phenolic compounds were separated by preparative TLC; compound A was most likely an isoflavone and the UV spectrum of compound B was similar to that of 2-hydroxychalcone.     

ANTIOXIDANT ACTIVITY OF PHENOLIC FRACTIONS OF BEACH PEA (LATHYRUS MARITIMUS L.)

Beach pea meal was extracted with 80% (v/v) aqueous ethanol for 20 min at 80C. The extract was fractionated on a Sephadex LH-20 column using methanol as eluate. Five major fractions were isolated according to their UV absorption and relative content (%) of total phenolics. Antioxidant activity of these fractions was evaluated in a β-carotene-linoleate model system. Fraction II showed the best antioxidant effect by exhibiting the highest preventive activity against the bleaching of β-carotene. Further separation of this fraction on TLC indicated that it contained several compounds, including phenolic acids and trihydroxy phenolics such as flavones and flavonols.     

EFFECT OF BROAD BEAN AND PEA PHENOLICS ON THE ACTIVITY OF LIPASE AND LIPOXYGENASE

The total content of phenolics in broad beans ranged from 276 to 794 mg/kg of sample on a dry weight basis (dwb), while in peas varied from 144 to 691 mg/kg of sample (dwb). Broad beans contained a higher level of proanthocyanidins than peas. Proanthocyanidins were the predominant phenolics in beans and peas. Phenolics were mostly located in seed coats. The methanolic extracts of phenolics from both broad beans and peas showed great inhibitory effects towards both lipase and lipoxygenase activities.     

月见草的特殊功效及其开发前景

月见草入药主要是月见草油对心脑血管疾病的治疗和预防，极高的营养价值仅在饮料上有初步应用，而作为食品学譬油和添加剂则刚刚受到关注，月见鲜花浸膏用于化妆品加香，效果极佳．有保健美容的功效，今后，在营养食品开发应用上应深入研究。     

TOCOPHEROLS AND PHOSPHOLIPIDS ENHANCE THE OXIDATIVE STABILITY OF BORAGE AND EVENING PRIMROSE TRIACYLGLYCEROLS

The effect of individual phospholipids and tocopherols as well as their combinations on the oxidative stability of borage and evening primrose triacylglycerols (TAG) was investigated. Based on conjugated dienes (CD) and 2-thiobarbituric acid reactive substances (TBARS) formed in borage and evening primrose TAG, the antioxidant effectiveness of phosphatidylcholine (PC), was higher than that of phosphotidylethanolamine (PE) in borage TAG while the reverse was observed for evening primrose TAG. Meanwhile, a synergistic effect between tocopherols and phospholipids in both borage and evening primrose TAG was noted. The most effective combination in borage TAG was that of PC and α-tocopherol, while PE with α-tocopherol exerted the best effects in evening primrose TAG. Therefore, the antioxidant effectiveness of phospholipids may vary depending on their fatty acid composition, nature of the functional groups and the chemical composition of the lipid system in which they are examined. The results also demonstrate the importance of minor components of vegetable oils on their oxidative stability.     

ANTIOXIDANT ACTIVITY OF PHENOLIC FRACTIONS OF WHITE BEAN (PHASEOLUS VULGARIS)

An extract from white bean seeds was prepared using 80% (v/v) acetone. Four fractions (I-IV) -were separated from the crude extract on a Sephadex LH-20 column using methanol as the mobile phase. The antioxidant activity of fractions was investigated in a β-carotene-linoleate model system. For individual fractions, IV spectra were recorded and the content of total phenolics was determined. Fractions were also characterized based on the number of phenolic compounds, and their antioxidant activity determined by TLC analysis. The presence of caffeic, p-coumaric, ferulic, and sinapic acids in the form of free and estrified compounds was found in fraction IV. One dominant phenolic compound was present in fraction III after acid hydrolysis with a maximum absorption at 278 nm. Results of the β-carotene-linoleate model system indicated that antioxidant activity of separated fractions did not correlate exactly with their content of total phenolic compounds and were in the order of IV>III>II>I. Individual fractions contained several phnolic compounds as noted by TLC. Spots on the plates sprayed with a solution of p carotene-linoleate indicated that these compounds can act as natural antioxidants. Absorption maxima in the W spectra showed that jlavonoids, and not phenolic acids, were the main phenolic compounds present in the separated fractions.     

OXIDATIVE DETERIORATION OF BORAGE AND EVENING PRIMROSE OILS AS ASSESSED BY NMR SPECTROSCOPY

A facile¹H NMR spectroscopic method was employed to monitor oxidation of borage (BO) and evening primrose (EPO) oils under Schaal oven conditions over a 96 h period at 60C. Relative changes of aliphatic to olefinic (R_ao) and aliphatic to diallylmethylene (R_ad) proton ratios during oxidation of these oils were calculated. An increase in R_ao and R_ad values was observed over the entire storage period. A highly significant correlation (r=0.950–0.995) existed between the conjugated diene values and changes in R_ao and R_ad during oxidation of both oils. The correlation coefficient between 2-thiobarbituric acid reactive substances (TBARS) and changes in R_ao and R_ad values was in the range of 0.972–0.982. Therefore, ¹H NMR methodology may be used as an effective means to simultaneously estimate both primary and secondary oxidation changes in borage and evening primrose oils.     

CRANBERRY PHENOLICS-MEDIATED ELICITATION OF ANTIOXIDANT ENZYME RESPONSE IN FAVA BEAN (VICIA FABA) SPROUTS

The antioxidant response mechanism by which phenolic phytochemicals show their positive benefits in plants and animals is not very well understood. The ability of cranberry juice powder (CP), ellagic acid (EA), rosmarinic acid (RA) and their synergies to elicit a phenolic response in germinating fava bean was investigated. Results indicated that elicitation with CP, EA, RA and their synergies resulted in increased endogenous phenolic synthesis linked to the stimulation of pentose phosphate pathway (PPP). Further, the stimulation of PPP was linked to the accumulation of free proline, suggesting a possible coupling of proline biosynthesis with PPP. Elicitation also resulted in the stimulation of guaiaicol peroxidase, suggesting a possible involvement in modulating structural development of the germinating sprout. Exogenous phenolic elicitation also resulted in the formation of malondialdehyde, which was gradually reduced because of the activation of antioxidant enzyme systems superoxide dismutase and catalase. The results indicate that the possible mode of action of exogenous phenolic phytochemicals in dark germinating fava bean could be by stimulating the PPP linked to proline biosynthesis and by the activation of the antioxidant enzyme system. The results also suggest that pure exogenous phenolics, EA and RA appeared to be effective when they were present in a cranberry phenolic background, suggesting a possible synergistic mode of action between EA, RA and cranberry phenolics in generating an endogenous fava bean antioxidant enzyme response.     

OPTIMIZATION OF EMULSIFICATION AND MICROENCAPSULATION OF EVENING PRIMROSE OIL AND ITS OXIDATIVE STABILITY DURING STORAGE BY RESPONSE SURFACE METHODOLOGY

ABSTRACT

Microencapsulation is a technique by which small droplets of liquid or solid particles are coated with a thin film of wall materials to protect susceptible ingredients in food products to assure their quality or effectiveness. Microencapsulation of liquid lipid into powdery matrixes of wall materials includes two unit operations: emulsification of the lipid with an aqueous solution of wall material and drying of the emulsion. The effects of hydrophile–lipophile balance (HLB) value, emulsifier content and oil content on the evening primrose oil‐in‐water emulsion stability were studied by response surface methodology (RSM). The HLB value, emulsifier content and oil content all had significant effects on the emulsion stability (P < 0.05). Of them, the HLB value and emulsifier content contributed more effects than the oil content. The optimized HLB value, emulsifier content and oil content were used to mix with wall materials: gum arabic (GA), maltodextrin (MD) and/or sodium caseinate (NaC). The oil was encapsulated with these materials individually or in combination by spray‐drying, and their oxidative stability during storage was compared. The microcapsules with a single wall material were relatively susceptible to oxidation than those with multiple wall materials. The most desirable composition of the mixture of GA, MD and NaC by RSM was 17.2, 75 and 7.8%, respectively.

PRACTICAL APPLICATIONS

Response surface methodology (RSM) provided a valuable means to help us understand the relative or interactive effects of three important parameters: HLB value, emulsifier content and oil content on the emulsion stability of the oil‐in‐water (o/w) system. The information obtained would be useful for the preparation of similar o/w emulsion system as needed in some product development for foods. In addition, the effects of gum arabic, maltodextrin and sodium caseinate on the oxidative stability of microencapsulated oil were also studied by RSM. The results revealed the relative or interactive effects of these materials and gave the optimal conditions in minimizing the oxidative instability in this study. Since these wall materials are readily available and widely used in a variety of products, the information provided by this study would be useful for product‐developing professionals to use these materials more efficiently in terms of obtaining optimal microencapsulated products against lipid oxidation and cost effectiveness.     

大豆异黄酮及大豆皂甙的抗氧化性研究

以脱脂大豆胚芽为原料,提取、分离纯化得到大豆异黄酮和大豆皂甙产品.通过超氧阴离子及过氧化氢清除实验、还原能力测定及抑制猪油氧化能力测定实验对大豆胚芽中的大豆皂甙和大豆异黄酮提取物的抗氧化性能进行了比较系统的评价.     

ANTIOXIDANT ACTIVITY OF WHEAT CARYOPSES AND EMBRYOS EXTRACTS

Phenolic compounds were extracted with 80% methanol from caryopses and embryos of wheat (cv. Alba and Elena). In extracts the content of total phenolics was determined and UV spectra recorded. For all extracts the antioxidant activity in a β-carotene-linoleate model system, scavenging effect on DPPH radical, and reducing power were examined. Extracts of wheat embryos were characterized by a higher content of total phenolics. UV spectra of phenolic compounds extracted from wheat caryopses were characterized by maxima close to 320 nm due to phenolic acids, and by maxima at shorter wavelengths (272–280 nm) attributed to other phenolic compounds. The antioxidant activities of extracts from caryopses in a β-carotene-linoleate model system were higher than those from embryos. The results so obtained were similar to those observed previously for extracts of rye and triticale grains and leguminous seeds. The scavenging effect of wheat extracts on DPPH radical and their reduction power were weak, but those for embryos extracts were somewhat stronger.     

半叶马尾藻中岩藻聚糖硫酸酯的提取纯化及抗氧化研究

从半叶马尾藻中提取得到的岩藻聚糖硫酸酯（SPF）,采用十六烷基三甲基溴化铵（CTAB）沉淀法纯化得SPF1,然后经DEAEC-52柱层析得F1和F2两个级分。化学组成分析表明,这4个级分均含有岩藻糖、硫酸基、糖醛酸以及少量的蛋白质。采用比色法研究岩藻聚糖硫酸酯清除羟基自由基（&#183;OH）及超氧阴离子自由基（O2^-&#183;）的作用,结果显示,4种岩藻聚糖硫酸酯级分均有清除活性氧自由基的能力,并且随着纯度的提高其抗氧化能力越强。