Egyptian mango by-product 1. Compositional quality of mango seed kernel

Egyptian mango seeds were collected as wastes from local fruit processing units and the kernels were separated and dried. This study was carried out on mango seed kernels to clarify their proximate composition, amino acids, phenolic compounds and the characteristics of the extracted oil including unsaponifiable matter constituents, lipid classes and fatty acid composition. Mango seed kernels contained a considerable amount of total phenolic compounds, total lipid, unsaponifiable matter, and a low amount of crude protein, but the quality of protein was good because it was rich in all essential amino acids. Eight phenolic compounds were identified; tannin and vanillin were in highest amounts. Unsaponifiable matter showed the occurrence of high amounts of squaline followed by sterols and tocopherols. Stearic acid was the main saturated fatty acid, while oleic acid was the major unsaturated fatty acid in all lipid classes. The fatty acid composition of total lipid and neutral lipid was similar, while phospholipid had a high amount of palmitic, linoleic and linolenic acids.     

Effect of Infrared Heating on the Formation of Sesamol and Quality of Defatted Flours from Sesamum indicum L.

ABSTRACT:  Infrared (IR) heating offers several advantages over conventional heating in terms of heat transfer efficiency, compactness of equipment, and quality of the products. Roasting of sesame seeds degrades the lignan sesamolin to sesamol, which increases the oxidative stability of sesame oil synergistically with tocopherols. IR (near infrared, 1.1 to 1.3 μm, 6 kW power) roasting conditions were optimized for the conversion of sesamolin to sesamol. The resultant oil was evaluated for sesamol and tocopherol content as well as oxidative stability. The defatted flours were evaluated for their nutritional content and functionality. IR roasting of sesame seeds at 200 °C for 30 min increased the efficiency of conversion of sesamolin to sesamol (51% to 82%) compared to conventional heating. The γ-tocopherol content decreased by 17% and 25% in oils treated at 200 and 220 °C for 30 min, respectively. There were no significant differences in the tocopherol content and oxidative stability of the oil. Methionine and cysteine content of the flours remained unchanged due to roasting. The functional properties of defatted flours obtained from either IR roasted or conventionally roasted sesame seeds remained the same.
Practical Applications: Sesame oil is stable to oxidation compared to other vegetable oils. This stability can be attributed to the presence of tocopherols and the formation of sesamol, the thermal degradation product of sesamolin—a lignan present in sesame. Roasting of sesame seeds before oil extraction increases sesamol content which is a more potent antioxidant than the parent molecule. The conversion efficiency of sesamolin to sesamol is increased by 31% by infrared roasting of seeds compared to electric drum roasting. This can be used industrially to obtain roasted oil with greater oxidative stability.     

The relationship of antioxidant components and antioxidant activity of sesame seed oil

Although sesame seed oil contains high levels of unsaturated fatty acids and even a small amount of free fatty acids in its unrefined flavored form, it shows markedly greater stability than other dietary vegetable oils. The good stability of sesame seed oil against autoxidation has been ascribed not only to its inherent lignans and tocopherols but also to browning reaction products generated when sesame seeds are roasted. Also, there is a strong synergistic effect among these components. The lignans in sesame seed oil can be categorized into two types, i.e. inherent lignans (sesamin, sesamolin) and lignans mainly formed during the oil production process (sesamol, sesamolinol, etc.). The most abundant tocopherol in sesame seed oil is γ‐tocopherol. This article reviews the antioxidant activities of lignans and tocopherols as well as the browning reaction and its products in sesame seed and/or its oil. It is concluded that the composition and structure of browning reaction products and their impacts on sesame ingredients need to be further studied to better explain the remaining mysteries of sesame oil. © 2014 Society of Chemical Industry     

Antioxidant activity of brown pigment and extracts from black sesame seed (Sesamum indicum L.)

The antioxidant activities of brown pigment, extract of n-hexane and extract of supercritical carbon dioxide extraction of black sesame seeds were investigated in this study. Kinetics of anti-radical activity showed that the reaction between DPPH and brown pigment of sesame seed was rapid and reached the steady state in 10 min. Extracts from supercritical carbon dioxide extraction and n-hexane extraction reacted with DPPH slowly and the absorbance became stable after 35 min. However, α-tocopherol and trolox were rapid while the kinetic behaviour of BHA was intermediate. The brown pigment of sesame seed also showed a lower EC₅₀ (13.5 μg ml⁻¹) than the other two extracts and α-tocopherol, which was about 7–10 fold of the antioxidant activity of the supercritical carbon dioxide extract and the n-hexane extract. The ferric thiocyanate (FTC) method also showed that the brown pigment of sesame seed provided higher inhibition activity against lipid peroxidation at 200 μg ml⁻¹ than did the supercritical carbon dioxide extract an n-hexane extract at 1 mg ml⁻¹. However, the activities of the supercritical carbon dioxide extract and n-hexane extracts were significantly higher than that of α-tocopherol. In the linoleic acid system, the brown pigment of black sesame seed showed an equal antioxidant activity to BHA and higher than trolox and α-tocopherol. The results indicated that the brown pigment of sesame seed possessed excellent antioxidant activity.     

Optimization of Hull‐Less Pumpkin Seed Roasting Conditions Using Response Surface Methodology

Abstract: Response surface methodology (RSM) was applied to optimize hull‐less pumpkin seed roasting conditions before seed pressing to maximize the biochemical composition and antioxidant capacity of the virgin pumpkin oils obtained using a hydraulic press. Hull‐less pumpkin seeds were roasted for various lengths of time (30 to 70 min) at various roasting temperatures (90 to 130 °C), resulting in 9 different oil samples, while the responses were phospholipids content, total phenols content, α‐ and γ‐tocopherols, and antioxidative activity [by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free‐radical assay]. Mathematical models have shown that roasting conditions influenced all dependent variables at P < 0.05. The higher roasting temperatures had a significant effect (P < 0.05) on phospholipids, phenols, and α‐tocopherols contents, while longer roasting time had a significant effect (P < 0.05) on γ‐tocopherol content and antioxidant capacity, among the samples prepared under different roasting conditions. The optimum conditions for roasting the hull‐less pumpkin seeds were 120 °C for duration of 49 min, which resulted in these oil concentrations: phospholipids 0.29%, total phenols 23.06 mg/kg, α‐tocopherol 5.74 mg/100 g, γ‐tocopherol 24.41 mg/100 g, and an antioxidative activity (EC₅₀) of 27.18 mg oil/mg DPPH. Practical Application: A well‐defined roasting process is very important for the food industry to be able to produce pumpkin seed oil with desirable nutritive and chemical characteristics of this unique salad oil, which changes during the roasting. This study contributes to the knowledge of a product design process for the roasting conditions of naked pumpkin seeds based on results that have demonstrated that an increase in roasting temperature significantly increased the biochemical values and antioxidant properties of the obtained virgin oils.     

Antioxidative activity of the crude extract of lignan glycosides from unroasted Burma black sesame meal

Sesame seed contains lignans and lignan glycosides. The antioxidative activity of the crude extract of lignan glycosides obtained from unroasted defatted black sesame seeds was investigated in this study. The components responsible for the antioxidative activity were also studied. The unroasted black sesame seeds, after defatted with n-hexane, were extracted with 80% methanolic solution to prepare for the crude extract of lignan glycosides. After chromatographic separation of this crude extract with octadecylsilane (ODS) column (2.5 cm i.d.×100 cm), four fractions (Fr1, Fr2, Fr3, Fr4) of the crude extract were obtained from the eluents of 25, 50, 75% aqueous methanolic solution and 100% methanol, respectively. Among them, Fr2 and Fr3 showed better antioxidative activity by 2,2-Diphenyl-1-picrylhydrazyl hydrate (DPPH) antioxidative assay. These two fractions were further purified by preparative HPLC (Hyperprep 100 C18 column; 20 mm i.d.×250 mm) and the main constituents were found to be lignan glycosides and some unknown brown materials. It was interesting to find that the brown materials (in Fr2) exhibited exceptional DPPH free radical scavenging effect, whereas the identified sesaminol triglucoside in Fr2 and sesaminol diglucoside in Fr3 possess no such activity. Using Cu⁺²-induced oxidation of human low-density lipoprotein (LDL) for the antioxidative assay, similar results were observed. Seaminol triglucoside and sesaminol diglucoside showed no effect on the extension of lag phase, while the brown materials had excellent inhibitory effect on the oxidation of LDL. Furthermore, natural antioxidants such as γ-tocopherol, sesamol and sesaminol were not detected in the crude extract of lignan glycosides. Our findings suggest that the brown materials present in Fr2 had a significant contribution to the antioxidative activity of the crude extract of lignan glycosides. Identification of the responsible components is underway.     

Antioxidant activities of defatted sesame meal extracts in cooked turkey breast and thigh meats

The antioxidant properties of methanolic extract of raw and roasted (at 200 °C for 60 min) defatted sesame‐meal in turkey breast and thigh meat systems were determined. The TBARS values of turkey breast and thigh meat added with 0.1% of roasted defatted sesame‐meal extract were 18.8% and 24.7%, respectively, lower than those of untreated controls after 5 days of storage. The turkey meats added with roasted defatted sesame‐meal extract had higher a* and b* values than those of controls due to the browning effects occurred in sesame seeds during roasting. The amounts of volatile hydrocarbons (pentane, hexane, heptane, and octane) and carbonyls (propanal, butanal, pentanal, hexanal and heptanal) significantly decreased by the addition of roasted defatted sesame‐meal extract. In particular, the amount of hexanal, the most predominant volatile compound in the cooked turkey meat, decreased by 74% and 83% in turkey breast and thigh meat, respectively. However, raw defatted sesame‐meal extract did not show significant antioxidant activity in turkey meats. These results indicated that heat treatment of sesame‐meal increased the antioxidant activities of methanolic extract of defatted sesame meal. Copyright © 2007 Society of Chemical Industry     

Antioxidant activity of the fractions separated from the unsaponifiable matter of bene hull oil

The unsaponifiable matter (USM) of bene hull oil were separated into hydrocarbons (7.3%), carotenes (7.1%), tocols (48.4%), linear and triterpenic alcohols (1.7%), methyl sterols (11.2%), sterols (6.2%), and triterpenic dialcohols (18.0%). Regardless hydrocarbons fraction, the whole USM and all fractions had the EC₅₀ (mg/ml) value significantly lower than (USM, 0.99; tocols, 1.05; carotenes, 3.93; triterpenoids, 1.74–9.89) that of α-tocopherol (36.7). α-Tocopherol, the whole USM, and all fractions were able to increase significantly the stability of sunflower oil at 50 °C, so that the highest stabilizing effect belonged to the USM fractions with no significant differences amongst them, followed by the whole USM and α-tocopherol. The sunflower oil had an OSI (oil/oxidative stability index) of 3.54 h, which was considerably promoted by some of components (tocols, 4.35; hydrocarbons, 4.43 h; USM, 4.5 h; triterpenic alcohols, 5.1 h; carotenes, 5.49 h). The FRAP and DPPH tests showed nearly similar results.     

Determination of optimum processing conditions for hot‐air roasting of hulled sesame seeds using response surface methodology

Sesame paste (tahin) is produced by milling hulled, roasted, sesame seeds. In this study, a hot‐air roasting process for the production of sesame paste was optimised by response surface methodology (RSM) over a range of air temperatures (120–180 °C) for various times (30–60 min). The colour parameters (L, a and b values), browning index (BI), hardness, fracturability and moisture content of the seeds were used as response parameters to develop predictive models and optimise the roasting process. Increases in roasting temperature and time caused increases in the a and b values and in the BI. The hardness and fracturability of seeds also decreased with increasing roasting temperature and time. The quadratic and linear models developed by RSM adequately described the changes in the colour values and textural parameters, respectively. The result of RSM analysis showed that all colour parameters and textural parameters should be used to monitor the roasting of sesame seeds in a hot‐air roaster. To obtain the desired colour and texture, the optimum roasting range for production of sesame paste was determined as 155–170 °C for 40–60 min. Copyright © 2006 Society of Chemical Industry     

Aqueous enzymatic sesame oil and protein extraction

In the present work we evaluated five enzyme-mixtures (Protex 7L, Alcalase 2.4L, Viscozyme L, Natuzyme, and Kemzyme) for their effectiveness in extracting the oil and protein recovery from sesame seeds during an enzyme-assisted aqueous extraction (EAAE) process. Alcalase 2.4L was found to be the best for attaining a high oil yield (57.4% of the total oil content in the seed), whereas, the maximum amount of protein (87.1% of the total seed protein), was recovered in the aqueous phase with Protex 7L. The quality attributes such as fatty acids profile, density, refractive index, free fatty acid contents, iodine value, colour, saponification number and unsaponifiable matter of the sesame oil, extracted by aqueous enzymatic process, were comparable with that of the control (oil extracted without enzyme treatment) and hexane-extracted oil (HEO), revealing no significant (p > 0.05) variations among oils, produced by either of the methods. The oxidative stability state of the enzyme-extracted oil (EEO) was noted to be considerably improved relative to the control and HEO. The amount of tocopherols for the oils, produced by the enzyme–adjuvant was found to be higher than the control and HEO. An appreciable increase in the antioxidant activity as assessed by determinations of total phenolic contents, DPPH radical scavenging capacity, and inhibition of linoleic acid oxidation of EEO was also established. Overall, the present results revealed improvement in the quality of the EEO while a major portion of the food grade protein was also extracted in the aqueous phase.     

The effect of sterols on the oxidation of edible oils

The effect of sterols on the oxidation of a triglyceride mixture, similar in composition to olive oil, has been studied at 180°C. Δ⁵-Avenasterol and fucosterol are effective as antioxidants, whilst other sterols, including cholesterol and stigmasterol, are ineffective. The antioxidant effect of Δ⁵-avenasterol increases with concentration in the range 0·01% to 0·1%.An hypothesis is presented to explain the effectiveness of the sterols as antioxidants. It is concluded that lipid free radicals react rapidly with sterols at unhindered allylic carbon atoms. Isomerisation leads to a relatively stable allylic tertiary free radical, which is slow to react further, and this interrupts the autoxidation chain.     

Effect of Seed Roasting Conditions on the Antioxidant Activity of Defatted Sesame Meal Extracts

ABSTRACT: Antioxidant activities of defatted sesame meal extract increased as the roasting temperature of sesame seed increased, but the maximum antioxidant activity was achieved when the seeds were roasted at 200°C for 60 min. Roasting sesame seeds at 200°C for 60 min significantly increased the total phenolic content, radical scavenging activity (RSA), reducing powers, and antioxidant activity of sesame meal extract; and several low-molecular-weight phenolic compounds such as 2-methoxyphenol, 4-methoxy-3-methylthio-phenol, 5-amino-3-oxo-4-hexenoic acid, 3,4-methylenedioxyphenol (sesamol), 3-hydroxy benzoic acid, 4-hydroxy benzoic acid, vanillic acid, filicinic acid, and 3,4-dimethoxy phenol were newly formed in the sesame meal after roasting sesame seeds at 200°C for 60 min. These results indicate that antioxidant activity of defatted sesame meal extracts was significantly affected by roasting temperature and time of sesame seeds.     

Effects of different kind of sesame materials on the physical properties of gomatofu (sesame tofu)

Gomatofu (sesame tofu) is one of the traditional Japanese healthy foods and is representative of all shojin (vegetarian) dishes. Gomatofu, one of the mixed gels consisting of kudzu (arrowroot) starch and sesame, possesses an extremely unusual textural characteristic which is soft, smooth, and springy. The textural properties are greatly influenced by preparation, ingredients and roasting conditions of sesame seeds. Hence there are many kinds of sesame materials which can be used to prepare gomatofu such as white, black, huskless or not and roasted or unroasted sesame materials, in this study, the effects of these materials on the physical properties of gomatofu were studied. The sample of Ra-W prepared with unroasted huskless sesame seed had the least hardness, but mouthfeel of this sample were the highest. The samples of Ro-B and Ro-W prepared with roasted husk (black and white) sesame seed were evaluated to have the best palatability because of their superior springiness. It was clarified that different kinds of sesame materials affected the forming of structure and physical properties of gomatofu, because the chemical components were different from varieties of sesame materials.     

樟树籽油抗氧化能力及物质基础研究

植物油中天然抗氧化成分对油脂的加工、货架期及营养品质具有重要影响。为研究樟树籽油抗氧化活性及物质基础,本文分别对其脂肪酸组成、不皂化物含量、总酚含量和DPPH自由基清除率进行测定,分析总多酚及不皂化物对樟树籽油抗氧化活性的贡献率,明确樟树籽油抗氧化活性物质基础。结果表明,樟树籽油中主要为中链脂肪酸癸酸和月桂酸,二者含量占总脂肪酸的94.80%,不皂化物含量为0.55±0.01% ,总多酚含量为33.07 ±0.63 mg.kg_^-1。樟树籽油对DPPH自由基清除率的IC₅₀值为0.13 g.mL_^-1。相同质量浓度的樟树籽油、不皂化物和总多酚对DPPH自由基清除率分别为98.92±1.58%、38.49±0.66%、49.60±3.78%。因此,不皂化物及总酚对樟树籽油抗氧化贡献率分别为38.91%、50.14%。研究结果表明樟树籽油具有较强的抗氧化能力,其抗氧化活性物质主要为多酚类成分和不皂化物,二者对樟树籽油抗氧化能力的总贡献率高达89.05%。本研究初步明确了樟树籽油的抗氧化活性成分,可为樟树籽油的开发利用奠定基础。     

Effect of endogenous antioxidants of sesame seeds and sesame oil to the thermal stability of edible vegetable oils

Differently processed sesame seeds were used for the preparation of sesamol, seed extract, oil extract or unsaponifiable matter. Analysis of these sesame extracts revealed that dehulling and roasting of seeds had an adverse effect on their lignan and phenolic compounds content. Various concentrations of the extracts were incorporated in vegetable oils and their effectiveness in retarding the oxidative deterioration of oils was evaluated. Additionally, the formation of oxidation products in these oil samples was correlated with their antioxidant activity and their sesamol and phenolic compounds content. Results indicated that decomposition of phenolic compounds present in oil samples induced a significant reduction in their linoleic acid peroxidation inhibition capacity and a corresponding increase in their oxidative rancidity. Sesame seed extract was the most effective in protecting oils from oxidation, suggesting that seed extract, especially the one prepared from coated-unroasted sesame seeds, may have potential application as a source of natural antioxidants in oil industry.     

Effects of Roasting Conditions on the Changes of Stable Carbon Isotope Ratios (δ13C) in Sesame Oil and Usefulness of δ13C to Differentiate Blended Sesame Oil from Corn Oil

Abstract: Differentiating blended sesame oils from authentic sesame oil (SO) is a critical step in protecting consumer rights. Stable carbon isotope ratios (δ¹³C), color, fluorescence intensity, and fatty acid profiles were analyzed in SO prepared from sesame seeds with different roasting conditions and in corn oil blended with SO. Sesame seeds were roasted at 175, 200, 225, or 250 °C for 15 or 30 min at each temperature. SO was mixed with corn oil at varying ratios. Roasting conditions ranging from175 to 250 °C at the 30 min time point did not result in significant changes in δ¹³C (P > 0.05). Values of δ¹³C in corn oil and SO from sesame seeds roasted at 250 °C for 15 min were −17.55 and −32.13 ‰, respectively. Fatty acid ratios, including (O + L)/(P × Ln) and (L × L)/O, where O, L, P, and Ln were oleic, linoleic, palmitic, and linolenic acids, respectively, showed good discriminating abilities among the SO blended with corn oil. Therefore, using different combinations of stable carbon isotope ratios and some fatty acid ratios can allow successful differentiation of authentic SO from SO blended with corn oil. Practical Application: Adulteration of sesame oil with less expensive oils such as corn oil or soybean oil to reduce cost is a common unethical practice in Korea. Due to the unique and strong flavor of sesame oils that may mask other weaker flavors, however, differentiating authentic sesame oils from blended oils is difficult. This study showed that the roasting process did not significantly affect the ratios of the stable carbon isotope (δ¹³C) in sesame oils. δ¹³C was confirmed to be a reliable parameter. Moreover, some fatty acid ratios were designed to discriminate between blended sesame oil with corn oil and authentic sesame oil.     

Polyphenolic profile,antioxidant properties and antimicrobial activity of grape skin extracts of 14 Vitis vinifera varieties grown in Dalmatia (Croatia)

The aim of the present study was to determine polyphenolic composition, related antioxidative and antimicrobial properties of grape skin extracts from 14 grape varieties (seven white and seven red grape) grown in Dalmatia (Croatia). The content of total phenols, flavonoids, catechins, flavanols and individual polyphenols ((+)-catechin, (−)-epicatechin, epicatechin gallate, procyanidin B1 and procyanidin B2, quercetin glucoside, resveratrol monomers, piceid and astringin) was variety dependent. Antioxidant properties were determined as DPPH radical-scavenging ability (IC₅₀), ferric reducing/antioxidant power (FRAP), Fe²⁺-chelating activity (IC₅₀), and using β-carotene bleaching assay. The high antioxidant capacity of all extracts, both red and white, has been observed and related to the relative amounts of polyphenolic compounds with good antioxidant properties. The antimicrobial activity was screened by broth microdilution test using Gram-positive (Staphylococcus aureus, Bacillus cereus) and Gram-negative bacteria (Escherichia coli O157:H7, Salmonella Infantis, Campylobacter coli). It was confirmed against all tested organisms. Minimum inhibitory concentrations (MICs), were found in the range 0.014–0.59 mg of gallic acid equivalents (GAE)/ml, with lower MICs of white cultivars, especially against Campylobacter and Salmonella.     

Lipid oxidation-related characteristics of gim bugak (Korean fried cuisine with <Emphasis Type="Italic">Porphyra</Emphasis>) affected by frying oil

The effect of frying oil on the lipid oxidation, antioxidants, and in vitro antioxidant activity of gim bugak was studied. Bugak was prepared by pan-frying at 180 °C in unroasted sesame, soybean, extra virgin olive, or palm oil. The degree of lipid oxidation based on conjugated dienoic acid and p-anisidine values was higher in the bugak fried in soybean or sesame oil with high contents of polyunsaturated fatty acids and tocopherols. However, the oil oxidation was lower in olive and palm oils, which showed higher degradation of tocopherols and polyphenols than in sesame or soybean oil during frying. Although the bugak fried in palm oil contained less antioxidants than that fried in soybean or sesame oil, the in vitro antioxidant activity was not different (p > 0.05). Results suggest that palm oil can replace unroasted sesame oil for the preparation of gim bugak with improved lipid oxidative stability and health functionality.     

Fat and fatty acids of white lupin (Lupinus albus L.) in comparison to sesame (Sesamum indicum L.)

The study was undertaken to compare fat and fatty acid profiles in white lupin (Lupinus albus ssp. albus) and sesame (Sesamum indicum L.), representing two different families, Fabaceae and Pedaliaceae. Fat levels were 10.74% and 55.44% in seeds of white lupin and sesame, respectively. The results indicated that oleic, linolenic and arachidic acids in seed fat were higher in white lupin than in sesame cultivars. Oleic acid was the predominant fatty acid in white lupin, whereas linoleic acid was predominant in sesame. Fat content (%) was statistically significantly correlated with linoleic, linolenic and arachidic acids at the genotypic level. The fatty acid composition of white lupin is useful for human consumption. Although oil content of white lupin was lower than that of sesame, white sweet lupin could be improved.