Perception of flavour in standardised fruit pulps with additions of acids or sugars

We hypothesised that adding sugars or acids to pulps derived from fruit of different genetic background, or of lower or higher carbohydrate status should give similar results until a threshold for sweetness or acidity perception in the pulp background was reached. Pulps made from fruit of Actinidia deliciosa ‘Hayward’—a fresh sweet-acid kiwifruit—and A. chinensis ‘Hort16A’—a sweet tropical flavoured kiwifruit, were compared. Flavour volatiles and background sugar and acid composition differed between the two fruit. Using high (14.1–14.5%) or low (11.5–11.9%) soluble solids (SS) pulps, trained tasters perceived added sugar as sweeter, confirming earlier research with consumers. Added acids (7 mmoles H⁺ 100 g⁻¹) reduced perceptions of sweetness and tasters perceived quinic acid to have a strong impact on the pulps tasted, resulting in a greater perception of acidity than addition of citric, ascorbic or malic acids. However perceptions of acidity also depended on background pulp composition. Addition of sugar or acid to pulps affected measured headspace volatiles. Volatile compounds affected included mid-chain length aldehydes, alcohols and esters, but only a few showed significant alteration. For example, hexanal, (E)-3-hexen-1-ol and (Z)-3-hexenol increased significantly when malic acid was added to ‘Hayward’ pulps. We suggest that the release of alcohols was associated with change in acidity and pulp metabolism rather than a ‘salting out’ effect. Perceived changes to banana and lemon flavours with both sugar and acid addition appear to be due to interactions in taster mouths or associated memories rather than release of specific volatiles.     

Polyphenolic and antioxidant content of white and blue corn (Zea mays L.) products

The polyphenolic and antioxidant content of white, Mexican blue, and American blue corns processed into nixtamal (cooked kernels), tortillas, and chips was investigated. A post-nixtamalization acidification treatment was assessed as a means to reduce polyphenolic and antioxidant losses. Similar anthocyanin composition (cyanidin 3-monoglycosides) and concentration (314 mg/kg) was observed for both blue corn genotypes as was their non-anthocyanin polyphenolic composition ((+)-catechin, free and esterified ferulic acid, and p-coumaric acid derivatives). Six derivatives of ferulic acid (88.8–816 mg/kg) along with the free form (2480 mg/kg), p-coumaric acid (6.6 mg/kg), two protocatechuic acid derivatives (4.2 and 14.2 mg/kg), and gallic acid (3.9 mg/kg) were identified in the white genotype. Both blue genotypes contained higher antioxidant capacity (>8.3 μmol Trolox equivalents/g) yet lower polyphenolic levels (3.6–4.4 g/kg) than the white genotype. Comparable anthocyanin losses were observed when the blue genotypes were processed into nixtamals (37%), tortillas (54%), and chips (78%) that correlated to polyphenolic (r = 0.91) and antioxidant capacity (r = 0.94) losses. Acidification was mainly effective in reducing anthocyanin (9–17%), polyphenolic (10%), and antioxidant capacity (6–14%) losses for the blue genotypes. This study compared polyphenolic and antioxidant content among corn genotypes and confirmed that acidification post-nixtamalization could reduce polyphenolic and antioxidant losses.     

Effects of irradiation on decolourisation and biological activity in Schizandra chinensis extracts

The fruit of Schizandra chinensis Baillon is a well-known traditional medicinal plant in Korea, China and Japan. We examined the effects of gamma irradiation on decolourisation and biological activity of S. chinensis fruit extracts to facilitate industrial applications. Samples were exposed to gamma-ray irradiation from 0.5 to 10 kGy. Irradiation of greater than 2 kGy markedly reduced the major colourant in S. chinensis fruit extracts, cyanidin-3-O-xylosylrutinoside (Cya-3-O-xylrut), by 80–90%. Biological activities, such as radical-scavenging activity and elastase inhibition activity, were not affected by gamma irradiation, but we observed a 12.3% increase in tyrosinase inhibition activity. There were negligible changes in the amounts of the major lignans schizandrin, gomisin A and gomisin N, following irradiation. These results indicated that gamma irradiation can selectively remove undesirable colour in S. chinensis extracts without adverse changes in biological activity.     

Air-dried capsicum annuum var. acuminatum medium and big: Determination of bioactive constituents,antioxidant activity and carbohydrate-hydrolyzing enzymes inhibition

In the present study the total phenols, flavonoids, carotenoids and capsaicinoids content, the in vitro antioxidant and hypoglycemic activities of extracts of air-dried fruits from two Capsicum annuum cultivars were investigated. A different composition between the two cultivars was evidenced. C. annuum var. acuminatum medium extract presented a major content of phenols, carotenoids, capsaicin and dihydrocapsaicin while C. annuum var. acuminatum big extract is characterized by the highest quercetin, luteolin and kaempferol content with 68.0, 87.6 and 29.7 μg/g dried weight, respectively, analyzed by HPLC. Medium pepper showed the highest radical scavenging activity in DPPH assay (IC₅₀ of 85.3 μg/ml) while big pepper have an interesting activity in ABTS assay (IC₅₀ of 16.4 μg/ml) and the highest inhibition of linoleic acid oxidation with an IC₅₀ value of 1.2 μg/ml after 30 min of incubation. A selective inhibitory activity against α-amylase was demonstrated for C. annuum var. acuminatum big lipophilic fraction (IC₅₀ values of 8.7 μg/ml). The obtained results suggest that C. annuum cultivars could be used as valuable flavor with functional properties for foods.     

Comparison of NIR and MIR spectroscopic methods for determination of individual sugars,organic acids and carotenoids in passion fruit

In this work, NIR and MIR spectroscopy was investigated and compared for predicting passion fruit ripening parameters as sugars, organic acids and carotenoids. Spectra of 56 samples of the lyophilized passion fruit were collected using an integrating sphere in NIR range and attenuated total reflectance accessory in MIR range. Individual sugars (sucrose, glucose and fructose), organic acids (malic and citric acids) and carotenoids (β-carotene) contents were determined by reference methods. Spectral and reference data were analyzed by principal component analysis. Partial least square regression (PLSR) was used to establish calibration models. MIR technique was better than the NIR technique for glucose (R²_v = 0.942), fructose (R²_v = 0.855), sucrose (R²_v = 0.818), total sugar (R²_v = 0.914) and citric acid (R²_v = 0.913) content determination. On the other hand, NIR was superior for total acids (R²_v = 0.903) content determination. For malic acid and β-carotene contents both methods were unsatisfactory due to low concentrations of these constituents in the passion fruits.     

Producing ice cream using a substantial amount of juice from kiwifruit with green,gold or red flesh

Ice cream prepared using a substantial amount of juice from kiwifruit with green, gold or red flesh may have consumer appeal, through the combination of kiwifruit's unique color, natural flavor and health-promoting constituents. The aqueous fractions from purees of kiwifruit with green, gold and red flesh (AFKWs) were added at 49% v/v to a basic low-fat ice cream mix that contained no commercial flavoring and coloring agents. The resultant ice creams were subjected to comparative product evaluation (e.g. overrun, melting behavior and rheological properties) and chemical analyses of bioactives (e.g. total extractable polyphenol content (TEPC), vitamin C, antioxidant capacity, polyphenol (PP) and carotenoid composition). Results revealed that both the pH pre-adjustment and pre-heating of the AFKW played critical roles in ice cream making. The ice creams retained the PP and vitamin C contents as well as natural color flavor of the kiwifruit used. The rheological properties of all ice creams showed non-Newtonian flow behavior, and the storage modulus G′ decreased in the same pattern following the order of green > gold > red. The melting rate, overrun and vitamin C content of the ice cream with green AFKW were the fastest, lowest and least, respectively. The TEPC and antioxidant capacity in the ice cream with red AFKW were the highest. The amounts of PPs and vitamin C were encouragingly high. Health beneficial compounds, dimethyl-caffeic acid hexoside, caffeic acid derivatives, protocatechuic acid, syringic acid, salicylic acid/ο-coumaric acid, lutein and beta-carotene, were detected in the final products. Thus, there are commercial possibilities for using AFKW which should be further evaluated.     

Chemical composition,antioxidant activity and sensory evaluation of five different species of brown edible seaweeds

The chemical and volatile composition as well as sensory profile of five brown edible seaweeds collected in the United Kingdom, was evaluated. The ash content was 190–280 mg/g, NaCl 35.1–115.1 mg/g, protein 2.9–6.0 g/g, and fat 0.6–5.8 g/g (dry basis). Fucus vesiculosus, Fucus spiralis and Ascophyllum nodosum showed higher antioxidant activities (DPPH and FRAP). Nucleotide concentrations were of the same order of magnitude as reported in other foods such as tomatoes or potatoes, except for F. vesiculosus where levels of nucleotides were 10 times higher. The fatty acids profile was dominated by oleic acid (21.9–41.45%), followed by myristic (6.63–26.75%) and palmitic (9.23–16.91%). Glutamic and aspartic acids (0.15–1.8 mg/g and 0.05–3.1 mg/g) were the most abundant amino acids. Finally, sensory and volatile analyses illustrated that Laminaria sp. had the strongest seaweed and seafood-like aroma and taste.     

Protein quality and identification of the storage protein subunits of tofu and null soybean genotypes,using amino acid analysis,one- and two-dimensional gel electrophoresis,and tandem mass spectrometry

The protein quality of 11 null and 2 tofu soybean genotypes were determined from their total protein content, their amino acid composition, and their glycinin and β-conglycinin contents. There were highly significant differences (P < 0.001) in their total storage proteins, and amino acid contents. Total protein among these genotypes ranged from 33 to 37%, with arginine being the third highest amino acid (7.4–10.9 g/100 g protein) followed by glutamic and aspartic acids. Methionine accounted for only 1.6–2.4 g/ 100 g of protein. All genotypes contained a good balance of essential amino acids (EAA₉), ranging from 43.5 to 47.3% of the total protein, limited only in methionine and possibly threonine and valine. Two-dimensional gel electrophoretic (2-DE) reference maps, using narrow range immobilized pH gradient (IPG) strips, revealed unique differences in the proteome, and subunit expression of glycinin and β-conglycinin, among these null genotypes, which can then be correlated with their protein quality. Out of a total of 111 basic (pH 6–11), and 223 acidic (pH 4–7) protein spots separated by 2-DE, 41 soybean storage protein spots were excised, and identified by liquid chromatography on-line with electro spray LCQ DecaXP tandem quadrupole time-of-flight mass spectrometry (LC/MS/MS). These methods will enable accurate evaluation of protein quality in soybeans, based on their protein digestibility-corrected amino acid score, assessment of the genetic variability of soybean genotypes, and serve as very effective tools for assisting plant breeders in their selection of high quality soybean varieties.     

Lipid and protein oxidation of α-linolenic acid-enriched pork during refrigerated storage as influenced by diet supplementation with olive leaves (Olea europea L.) or α-tocopheryl acetate

The objective of this study was to evaluate the effect of diet supplementation with olive leaves or α-tocopheryl acetate on lipid and protein oxidation of raw and cooked n− 3 enriched-pork during refrigerated storage. Enrichment of pork with α-linolenic acid through diet supplementation with linseed oil enhanced (p ≤ 0.05) lipid oxidation in both raw and cooked chops but had no effect (p > 0.05) on protein oxidation during refrigerated storage while decreasing (p ≤ 0.05) the sensory attributes of cooked pork. Diet supplementation with olive leaves or α-tocopheryl acetate had no effect (p > 0.05) on the fatty acid composition of pork but decreased (p ≤ 0.05) lipid oxidation while exerting no effect (p > 0.05) on protein oxidation in both raw and cooked α-linolenic acid-enriched chops stored and chilled for 9 days. Moreover, olive leaves and α-tocopheryl acetate supplemented at 10 g/kg and 200 mg/kg diet, respectively, exerted (p ≤ 0.05) a beneficial effect on the sensory attributes of cooked α-linolenic acid-enriched pork chops.     

Physicochemical and melissopalynological characterization of Estonian summer honeys

The samples of 14 honeys, retained from Estonian beekeepers, were analyzed for parameters such as pH, moisture content, free acidity, electrical conductivity, diastase activity, hydroxymethylfurfural (HMF) content and mineral content, including sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca). Fructose, glucose and disaccharide content were also identified and fructose/glucose ratio was calculated. In addition melissopalynological analyses were carried out for characterization of honeys. The mean values of analyzed honeys were: pH 3.8; moisture 17.3%; free acidity 20.4 mmol/kg; electrical conductivity 0.2 mS/cm; diastase activity 23.1 DN and HMF was below 3.8 mg/kg. Within the mineral content, potassium was quantitatively the most important mineral in the range of 125.79 to 1381.53 mg/kg followed by calcium of 20.37-63.65 mg/kg, magnesium 5.53-25.49 mg/kg and sodium 4.77- 19.44 mg/kg. The predominant sugar in honey samples was fructose having the mean value of 35.91 g/100 g followed by glucose 35.00 g/100 g. The disaccharide average content was 6.00 g/100 g. The melissopalynological analyzes showed that the most dominant pollens in honey samples were cruciferous (Cruciferae)-mainly rape (Brassica napus); rosacean (Rosaceae)-mainly raspberry (Rubus idaeus); white clover (Trifolium repens); sweet clover (Melilotus officinalis) and willow (Salix). The results of honey pollen profile analysis and calculated fructose/glucose ratios (0.89-1.17) both indicated to flower honeys. All of the analyzed honeys were found to meet European Legislation (EC Directive 2001/110) for all parameters.     

Protective role of litchi (Litchi chinensis Sonn.) flower extract against cadmium- and lead-induced cytotoxicity and transforming growth factor β1-stimulated expression of smooth muscle α-actin estimated with rat liver cell lines

The protective potential of litchi flower acetone extract (LFAE) against cadmium (Cd)- and lead (Pb)-induced hepatocytotoxicity, and transforming growth factor β1 (TGF-β1)-mediated activation of hepatic stellate cells (HSCs) were evaluated. Phenolic compounds were plentiful in LFAE (429 mg/g of dried extract); epicatechin (122.1 mg/g of dried extract), gentisic acid (60.2 mg/g of dried extract) and proanthocyanidin A2 (163.3 mg/g of dried extract) were the major flavanoid, phenolic acid and proanthocyanidin, respectively. Cd and Pb treatments significantly promoted lipid peroxidation and DNA damage in rat liver cells (Clone 9), and caused viabilities of the cells down. However, LFAE addition could dose-dependently decrease the Cd- and Pb-induced lipid peroxidation and DNA fragmentation, and increase the cell viabilities. LFAE could also suppress TGF-β1-induced activation of HSCs concluded from down-regulating expression of smooth muscle α-actin (αSMA). These effects should be attributed to the antioxidant action of phenolic compounds in LFAE.     

Evaluating eggplant (Solanum melongena L) genotypes for bioactive properties: A chemometric approach

Thirty four genotypes of eggplant and its wild relatives were evaluated for their total phenolics, flavonoid content and antioxidant capacity. Free radical scavenging was evaluated using four in-vitro assays, viz. FRAP (Ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), TEAC (Trolox equivalent antioxidant capacity) and DPPH (2, 2-diphenylpicrylhydrazyl). Total phenolics in eggplant showed a wide variation, ranging from 22.62 to 234.46 mg gallic acid equivalents (GAE)/100 g fw (244.28 to 2990.64 mg GAE/100 g dw). With the exception of Solanum aethiopicum and its accessions (Ac-1, Ac-2 and Ac-3), all wild relatives had significantly (p < 0.05) higher total phenolics and flavonoid content than cultivated ones. Total antioxidant capacity (FRAP) in wild genotypes ranged from 1.13 to 8.04 μmol Trolox (TE)/g. The hierarchy in decreasing order was Solanum khasianum > Solanum torvum > Solanum sisymbriifolium > Solanum incanum > Solanum integrifolium > S. aethiopicum. The antioxidant capacity correlated high with total phenolics in all assays. In cultivated group, JBR-99 and RCMBL-3 possessed high antioxidant capacity than the rest. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) revealed distinct similarity between JBR-99 (green), S. sisymbriifolium, S. khasianum and S. torvum. Overall results indicate that the wild species of S. torvum, S. incanum and S. sisymbriifolium are potential candidates for improving the functional quality of cultivated eggplant.     

Bioactive substance contents and antioxidant capacity of raw and blanched vegetables

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389–539 µg/100 g), blanched (510–818 µg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2–7.8 mg/100 g), blanched (0.67–3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene.Industrial relevanceBeans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work.     

贵州3种代表性猕猴桃种间特征香气成分比较分析

目的 了解贵州不同品种猕猴桃主要香气成分特征,同时探明不同品种猕猴桃的香气成分差异。方法 通过顶空固相微萃取-气相色谱-质谱 联用技术对贵长、红心及野生3种猕猴桃香气成分进行定性定量分析,计算香气物质的数量、含量,对相对香气活度值大于1的成分,利用热图进行分析。结果 3个猕猴桃品种共分析鉴定出102种香气物质,其中2-己烯醛、己醛、己醇、乙醇、(E)-2-己烯醇、乙酸等15种成分均在3个品种检测出。计算了30种成分的香气值,22种成分香气值大于1,贵长、红心及野生猕猴桃分别有14、14及9种。酯类、醇类含量最高的品种为野生猕猴桃,相对含量分别为59.32%、20.87%;醛类含量最高的品种为贵长、红心猕猴桃,相对含量分别为76.31%、74.95%。结论 本研究探讨了贵州3种代表性猕猴桃种间特征香气成分的差异 ,醛类、醇类和酯类是差异的主要来源,为贵州猕猴桃风味品质控制提供依据。     

Chemical composition and potential of some underutilized tropical biomass. I: fluted pumpkin (telfairia occidentalis)

The seeds of Telfairia occidentalis have been subjected to standard chemical analysis to evaluate their properties. Proximate analysis indicated a low moisture content (6.30 ± 0.50%). The ash content was slightly higher than the range recommended for compounding of animal feed (3.44 ± 0.06%). The carbohydrate content was low (16.5 ± 0.12%). Starch, however, constituted the dominant carbohydrate (62.5 ± 0.48), while three sugars, glucose, fructose and sucrose were detected in the seed. The crude protein in the seed was high (16.0 ± 0.03%), a value which compared favourably with high protein seeds and nuts. In all, 16 amino acids were detected in the protein. Glutamic acid showed the highest concentration (16.4 g 100 g⁻¹), while lysine showed the lowest (2.6 g 100 g⁻¹). The brown oil extracted from the seed (yield 48.6 ± 0.94) had the following physicochemical properties; acid value, 3.05 ± 0.80 g, saponification value 166 ± 1.34 mg/KOH g⁻¹, free fatty acids, 0.3 g and peroxide value 3.02 ± 0.07 mg Eq kg⁻¹. The iodine value (80.1 ± 0.10)g 100 g⁻¹ indicated a preponderance of unsaturated fatty acid. Four fatty acids were detected whilst unsaturated acids constituted 61.3 g. Triglyceride was the dominant lipid species while hydrocarbons, waxes, sterols and sterol esters and higher alcohols, were detected in the unsaponifable matter. Results of nutritionally valuable mineral elements indicated that potassium occurred at the highest concentration.     

Isolation and identification of an antiproliferative substance from fructose–tyrosine Maillard reaction products

We isolated a substance from fructose–tyrosine Maillard reaction products (MRPs) and investigated its antiproliferative effect on six human cancer cell lines. The ethyl acetate fraction of fructose–tyrosine MRPs showed a strong antiproliferative effect; this fraction was isolated and purified using silica gel column chromatography, semipreparative RP-HPLC, and recycling HPLC. The structure of the purified compound was determined using spectroscopic methods. The isolated compound was identified as 2,4-bis(p-hydroxyphenyl)-2-butenal (C₁₆H₁₄O₃, HPB242). HPB242 inhibited cell growth in a dose-dependent manner (10–80 μg/ml) on the six human cancer cell lines. The IC₅₀ values of HPB242 on the six human cancer cell lines were 17.34 μg/ml (MCF-7), 29.21 μg/ml (HCT-116), 34.57 μg/ml (H-460), 34.87 μg/ml (HepG2), 48.77 μg/ml (PC-3), and 55.83 μg/ml (MKN-45).     

Identification and quantification of phenolic acids and flavonol glycosides in Tunisian Morus species by HPLC-DAD and HPLC–MS

The total polyphenol and flavonoids in leaves of Morus alba var. alba, Morus alba var. rosa and Morus rubra were determined and identification of their components was carried out. The total content of phenolics varied between 345.20 and 631.53 mg gallic acid equivalents (GAE)/100 g dry weight (DW) basis. The total amount of flavonoids ranged between 193.87 and 398.33 mg rutin equivalents (RE)/100 g DW. Thirteen compounds were isolated by chromatography, and their structures determined to be mainly flavonol glycosides and phenolic acids. Three novel components were identified as kaempferol-7-O-glucoside, quercetin-3-O-β-glucoside-7-O-α-rhamnoside and quercetin-3-O-rhamnoside-7-O-glucoside, for the first time from mulberry leaves. Others known compounds were also identified.     

Oil content and fatty acid composition of some underutilized legumes from Nigeria

Three underutilized legumes from Nigeria, Brachystegia eurycoma, Tamarindus indica and Mucuna flagellipes, have been subjected to standard analytical techniques in order to evaluate proximate composition, physicochemical properties and contents of nutritional valuable elements and fatty acids of the seeds and oils. The proximate analysis indicated that the oil content was 5.87 ± 0.30, 7.20 ± 0.45 and 3.77 ± 0.21 g/100 g for B. eurycoma, T. indica and M. flagellipes, respectively. The seeds are rich in protein and carbohydrate, the protein content ranging from 11.82 ± 0.25 g/100 g–24.94 ± 0.18 g/100 g dry matter. These compare favourably with high protein animal sources like oyster, beef, pork and marine fishes. The iodine value of two of the oils place them in the non-drying group of oils, while the composition of all the oils compare well with those of rape seed, sesame, sunflower and groundnut seed oils. This suggests their use as edible oils.Analyses of the oils for fatty acids indicate that the oils contain linoleic acid which is one of the three essential fatty acids. The dominant fatty acids however are linoleic, palmitic, oleic and stearic acids with oleic acid having the highest percentage 24.13–31.50%. Eight nutritional valuable minerals were determined in the seed flours. The seeds are rich in potassium 52.1 mg/100 g–131 mg/100 g. They also contain significant concentration of iron 4.55 mg/100 g–8.20 mg/100 g.