Effect of sucrose on the anthocyanin and antioxidant capacity of mulberry extract during high temperature heating

This study aimed to elucidate how sucrose affects the anthocyanin and antioxidant capacity at low pH under high temperature. The interactive role of different sucrose concentrations (20%, 40%, 60%) and pH values (2, 3, 4) on a mulberry anthocyanin model system at different heating times was investigated. A520 (red color) decreased from 0 to 4 h and increased thereafter, degradation index of anthocyanin (DI) increased in the pure anthocyanin system during 68 h of heating. The samples with sucrose showed a DI peak at 17 h, which indicated that severe browning occurred after this period should be along with lower ratio of A420 and A520, and the latter high A520 came from a brown pigment instead of anthocyanin. Furfural content reached a maximum at 26 h during heating, and other caramelization intermediates showed a similar trend during this period. All samples, with or without sucrose, showed increase in polymeric and copigmented anthocyanin and a decrease in the monomeric ones during heating. The browning depends on the pH and sucrose concentration. Samples at pH 2 with higher sucrose showed the most significant browning and the increase of ferric reducing ability of plasma (FRAP) indicated that hydrolysis of sucrose might increase the antioxidant capacity. Further correlation analysis indicated that changes of antioxidant capacity during heating were closely related to the caramelization intermediate developed from sucrose in the sugar added system.     

Interactions between quercetin and catechin in a model matrix: Effects on the in vitro antioxidant behaviour

A hydroalcoholic medium at pH 3.5, containing Fe³⁺ and pyruvic acid, was used as the model matrix to study quercetin/catechin interactions and their possible influence on the antioxidant characteristics of the system. Incubation at 55 °C for a period of 20 days resulted in a complete disappearance of quercetin and a decrease of catechin concentration by almost 75%. Liquid chromatography–mass spectrometry analysis showed that the degradation products are mainly quercetin derivatives, but evidence also indicated that there may be the formation of a co-pigment-like, decarboxylated pyruvic acid-bridged quercetin/catechin adduct. The hydroxyl free radical scavenging activity (SA_HFR) exhibited significant negative correlation (P < 0.05) with both quercetin and catechin concentration whereas the antiradical activity (A_AR) was positively and significantly (P < 0.05) linked only with quercetin, stressing its importance as natural antioxidant agent with a key role in food systems.     

Chemical composition of wild edible mushrooms and antioxidant properties of their water soluble polysaccharidic and ethanolic fractions

Mushrooms have become attractive as functional foods and as a source of physiologically beneficial bioactive compounds. Herein, we describe and compare the chemical constituents (phenolic compounds, macronutrients, sugars, fatty acids, tocopherols and ascorbic acid) of four wild edible mushrooms widely appreciated in gastronomy: Armillaria mellea (Vahl) P. Kumm., Calocybe gambosa (Fr.) Donk, Clitocybe odora (Fr.) P. Kumm., Coprinus comatus (O.F. Müll.) Pers. Furthermore, the antioxidant activity of their water soluble polysaccharidic and ethanolic fractions was studied by three different in vitro assays. C. comatus revealed the highest concentrations of sugars (43.23/100 g dry weight), PUFA (77.46%), phenolic compounds (45.02 mg/kg), tocopherols (301.03 μg/100 g) and, among all of the fractions tested, its ethanolic fraction showed the highest antioxidant activity (EC₅₀ < 2.6 mg/ml). C. odora revealed one of the highest ascorbic acid (172.65 mg/100 g) contents and its water soluble polysaccharidic fraction showed the best antioxidant properties (EC₅₀ < 3.6 mg/ml) among the polysaccharidic fractions. The studied mushrooms species could potentially be used in well-balanced diets and as a source of bioactive compounds.     

Influence of extraction process on antioxidant capacity of spent coffee

Spent coffee that is produced in tons by restaurants and cafeterias, and consumers at domestic levels, could be a good opportunity to have an important source of natural antioxidants. The main aim of this work was to study the influence of several process factors on the antioxidant capacity extraction from spent coffee. Total phenolic compounds, radical scavenging activity (ABTS and DPPH) and browned compounds (Abs 420 nm) of spent coffee extracts obtained with continuous (Soxhlet 1 h and 3 h) and discontinuous methods (solid–liquid extraction and filter coffeemaker), several solvents (water, ethanol, methanol and their mixtures), successive extractions, and water with different pHs (4.5, 7.0 and 9.5) were carried out. Spent coffee extracts with the highest antioxidant capacity were obtained after one extraction with neutral water (pH 7.0) in a filter coffeemaker (24 g spent coffee per 400 mL water). Furthermore, spent coffee defatting and extract lyophilization allowed us to obtain spent coffee extracts powder with high antioxidant capacity that can be used as an ingredient or additive in food industry with potential preservation and functional properties.     

Mechanism of the interaction between insoluble wheat bran and polyphenols leading to increased antioxidant capacity

This study aimed to provide an in-depth investigation of the interaction between insoluble wheat bran and polyphenols. Treatment with tannic acid, but not gallic acid, increased the bound antioxidant capacity of insoluble wheat bran depending on its aqueous concentration (p < 0.05). Among the beverages tested (white and red wines, black and green tea infusions), treatment with green tea infusion caused the highest increase in the total antioxidant capacity. Temperature, time, air and pH were found to significantly affect the reaction between insoluble wheat bran and polyphenols. The bound antioxidant capacity of insoluble bran increased to above 100 mmol TE.kg^− 1 after treatment with green tea infusion at optimum conditions (50 °C, pH 9.0, no airflow). Concentration of free amino groups available in wheat bran significantly decreased (59.5%) after the treatment. The results suggested that polyphenols are oxidized to quinones under alkaline conditions further bound to free amino groups available on the surface of wheat bran.     

Neoformation of antioxidants in glycation model systems treated under subcritical water extraction conditions

In this work, the possibility of finding newly formed Maillard reaction products produced as a result of the subcritical water extraction (SWE) conditions is explored. Simplified powdered glycation model systems were prepared mixing amino acid (Lys, Arg or Ala) and glucose in a molar ratio 1:4. Samples constituted by glucose or amino acids alone were also prepared as controls. SWE was carried out at room temperature, 100 °C and 200 °C and 100 bar of pressure for 20 min. Different assays were performed in order to determine the extent of glycation by analyzing the decrease of free amino groups and/or the formation of Maillard reaction products (early, advanced and end products). Namely, formation of early colorless Maillard reaction products, Amadori compounds, was detected by ESI-MS; advanced glycation end products (AGEs) were detected by measuring the fluorescence intensity (λ_ex = 360 nm, λ_em = 460 nm) while end brown products were detected by reading the absorbance at 360 and 420 nm. Besides, the antioxidant capacity of the aqueous extracts was determined by using ABTS and ORAC_FL assays. Results obtained indicated the occurrence of the Maillard reaction under our specific extraction conditions. Early, advanced and end products were detected in the samples. Caramelization of sugar also occurred. As expected, the extent of the non-enzymatic browning depended on the intensity of the thermal treatment. Additionally, data on antioxidant activity suggested the formation of neoantioxidants. These compounds were predominantly formed at 200 °C. In conclusion, this report demonstrates the formation of antioxidant compounds in simplified glycation model systems under SWE conditions.     

Difructose anhydrides as quality markers of honey and coffee

Difructose anhydrides (DFAs) are pseudodisaccharides produced by condensation of two fructose molecules by means of caramelization reaction which takes place during heating of sugars or sugar-rich foodstuffs. The aim of this research was to evaluate the feasibility of DFAs as chemical markers of honey authenticity and sugar-roasted torrefacto coffee. DFAs were analysed by gas chromatography coupled to mass spectrometry after conversion to their trimethylsilyl (TMS) derivatives. α-d-fructofuranoside-1,2′:2,1′-α-d-fructofuranoside (DFA7) and α-d-fructofuranoside-1,2′:2,1′-β-d-fructopyranoside (DFA9) can be used as quality markers of honey and coffee. DFA7 and DFA9 were detected in honey added with 5% fructose and sucrose caramels and 15% of glucose caramels. Torrefacto coffees showed DFAs values ranged from 0.195 to 0.570 g/100 g whereas only traces were found in natural roasted coffees. Quantities from 0.073 to 0.189 g/100 g were measured in blends of natural and torrefacto roasted coffees. A relationship between DFAs content in torrefacto coffees and roasting conditions was observed. In conclusion, this study indicated that DFAs are useful chemical indicators to control honey authenticity and torrefacto coffee roasting.     

Yerba mate tea (Ilex paraguariensis): Phenolics,antioxidant capacity and in vitro inhibition of colon cancer cell proliferation

Mate tea (MT) is a rich source of phenolic compounds that vary depending on geographical origin and mode of preparation. Total phenolic concentration and antioxidant capacity of Mate tea (Ilex paraguariensis) products were determined in this work. In addition, a representative MT was tested for in vitro inhibition of human colon carcinoma cell proliferation. Total polyphenol concentration, was measured using Folin–Ciocalteau method, ranged from 90 to 176 mg gallic acid eq (GAE)/g dry leaves (DL) in traditional MT and from 40 to 113 mg GAE/g DL in MT added with other flavouring ingredients. It was estimated that a cup of tea (250 ml) containing one teaspoon (5 g) of instant MT could provide an average intake of 1.5 g GAE. Fresh tea (FT) from Mate leaves displayed high antioxidant capacity (85 ± 1%) and preferentially inhibited 50% of net growth of human colorectal adenocarcinoma cells CaCo-2 (GI₅₀ = 1.0 ± 0.03 μg/ml) and HT-29 (GI₅₀ = 105.2 ± 15.2 μg/ml) when compared with the CCD-33Co normal colon fibroblast cell line (GI₅₀ > 300 μg/ml). MT inhibited in vitro colon cancer cell proliferation possibly mediated via pro-oxidant activities, therefore represents a potential source of chemopreventive agents that deserve further investigation.     

Addition of seaweed (Laminaria digitata) extracts containing laminarin and fucoidan to porcine diets: Influence on the quality and shelf-life of fresh pork

A seaweed extract containing laminarin (L) and fucoidan (F) (L/F) was manufactured from brown seaweed (Laminaria digitata) in spray-dried (L/F-SD) and wet (L/F-WS) forms. The effect of supplementation of pig diets with L/F-SD and L/F-WS (L, 500 mg/kg feed; F, 420 mg/kg feed) for 21 days pre-slaughter, on quality indices of fresh M. longissimus dorsi (LD) steaks was examined. Susceptibility of porcine liver, heart, kidney and lung tissue homogenates to iron-induced (1 mM FeSO₄) lipid oxidation was also investigated. Dietary supplementation with L/F did not increase plasma total antioxidant status (TAS). In LD steaks stored in modified atmosphere packs (80% O₂:20% CO₂) (MAP) for up to 15 days at 4 °C, muscle pH, surface colour (CIE ‘L*’ lightness, ‘a*’ redness and ‘b*’ yellowness values) and microbiology (psychrotrophic and mesophilic counts, log CFU/g pork) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C > LF-SD > L/F-WS. A statistically significant reduction in lipid oxidation (P < 0.05) was observed in LD steaks from 75% of pigs (n = 6) fed with L/F-WS compared to controls. Iron-induced lipid oxidation increased in liver, heart, kidney and lung tissue homogenates over the 24 h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue homogenates. Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.     

Mandarin preservation by microwave-powered cold plasma treatment

Cold plasma treatment (CPT) was investigated as a nonthermal method for inhibiting Penicillium italicum and improving storability of mandarins (Citrus unshiu Marc.). Whole mandarin fruits or the peels were treated with cold plasma at 0.7 kPa using a microwave CPT system. The treatment variables were plasma-forming gases, plasma generation power, and treatment time. Nitrogen (N₂)-CPT at 900 W for 10 min, resulted in the highest inhibition of P. italicum (84% reduction in disease incidence), significantly increased the total phenolic content and antioxidant activity of mandarin peel after the treatment (p < 0.05), but did not significantly affect CO₂ generation, weight loss, content of soluble solids, titratable acidity, pH, ascorbic acid concentration (flesh), or surface color during storage at 4 and 25 °C. These results demonstrate the potential for CPT application as a postharvest technology for preserving mandarins, increasing the total phenolic content and antioxidant activity of mandarin peel.     

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.     

Southern Spain lamb types discrimination by using visible spectroscopy and basic physicochemical traits

The potential for using visible spectroscopy (400–700 nm) to classify six types (breed × production system) of lamb meat was investigated. Seven wavelengths namely 400, 410, 420, 450, 510, 610 and 670 nm were retained for the discriminant analysis. The basic meat physicochemical traits of Longissimus dorsi were also studied and a model including that information together with the spectra was developed to compare both accuracies. Then, Myoglobin content, water holding capacity, pH, a¹, 670 and 610 nm wavelengths, protein percentage, L¹, ash content, 450 and 420 nm wavelengths and moisture percentage were selected as variables for the development of the discriminant function. The data analysis showed that it was possible to discriminate the lamb types with accuracy around 83% using visible spectroscopy. However these results improved to 95% when using the reflectance together with basic physicochemical traits (12% better than using only the spectra).     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Effects of high hydrostatic pressure on the quality and shelf-life of jujube (Ziziphus jujuba Mill.) pulp

This study evaluated the effects of high hydrostatic pressure (HHP) on the microbial counts, physicochemical properties, bioactive compounds, and antioxidant capacity of jujube pulp. Additionally, this study compared the shelf life of jujube pulp following HHP (600 MPa/20 min) and thermal treatment (100 °C/10 min) during 40 days of storage at 4 °C and 15 °C. The microbial count of HHP-treated jujube pulp (≥ 400 MPa/20 min) was below the detection limit. Total soluble solids and total sugars were not significantly affected by HHP processing, and > 90% ascorbic acid was retained in HHP-treated samples. HHP slightly reduced pH and browning degree and increased total phenolic content, flavonoid content, and antioxidant capacity. HHP can be used as an alternative to thermal pasteurization of freshly squeezed jujube pulp.Industrial relevanceEffects of high hydrostatic pressure (HHP) processing and thermal treatment (TT) on microbiological quality, physicochemical properties, bioactive compounds and antioxidant activity in jujube pulp were investigated. Greater inhibition of microorganisms and better retention of ascorbic acid, total phenolics, flavonoid and antioxidant capacity were observed after HHP-treatment. The available data could be used to design the HHP parameters for high quality jujube juice. Further, this research would provide a useful method for preservation of jujube products and potential technical support for jujube commercial production.     

Lipopolysaccharide derived from the digestive tract provokes oxidative stress in the liver of dairy cows fed a high-grain diet

The aims of this study were to measure oxidative stress parameters and to investigate the molecular mechanism triggered by grain-induced subacute ruminal acidosis in mid-lactation cows. Twelve Holstein-Friesian cows with an average weight of 455 ± 28 kg were divided into 2 groups and subjected to 2 diets over 18 wk: either a low-grain (forage-to-concentrate ratio = 6:4) or a high-grain (forage-to-concentrate ratio = 4:6) diet based on dry matter. Being fed a long-term high-grain diet resulted in a significant decrease in rumen pH and a significant increase in ruminal lipopolysaccharide (LPS) at 4 h postfeeding in the morning. The increase was also observed in LPS concentrations in the portal vein, hepatic vein, and jugular vein blood plasma as well as reduced milk yield in a high-grain diet. Cows fed a high-grain diet had lower levels of catalase and glutathione peroxidase (GPx) activity and total antioxidant capacity than cows fed a low-grain diet; however, super oxide dismutase (SOD) activity and malondialdehyde (MDA) levels were higher in both the liver and the plasma of high-grain than in low-grain cows. Positive correlations were observed between plasma LPS versus hepatic MDA, plasma MDA, and hepatic SOD activity, whereas hepatic GPx and plasma GPx were negatively correlated with plasma LPS. The relative mRNA abundances of GPX1 and CAT were significantly lower in the liver of cows fed a high-grain diet than those fed a low-grain diet, whereas SOD1 was significantly higher in cows fed a high-grain diet than cows fed a low-grain diet. The expression levels of Nrf2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated, in cows fed a high-grain diet. Furthermore, nuclear factor E2-related factor 2 (Nrf2) total protein and mRNA levels were significantly lower than in low-grains. Our results demonstrate the relationship between the translocated LPS and the suppression of cellular antioxidant defense capacity, which lead to increased oxidative stress and suggests that the Nrf2-dependent antioxidant response may be affected by higher levels of LPS translocated to the bloodstream.     

Structure–mechanism relationship of antioxidant and ACE I inhibitory peptides from wheat gluten hydrolysate fractionated by pH

The aims of this study were to assess bioactive properties (ACE inhibition and antioxidant capacity) from wheat gluten hydrolysate peptides fractionated by pH (4.0, 6.0 and 9.0), to determine peptide action mechanism, and to relate it to the secondary structure and functional groups of peptides. Gluten hydrolysate extracts (GHE) were enriched in peptides with medium hydrophobicity and molecular weight (≈ 60% MH and 5.5 kDa, respectively). Gluten peptides inhibited ACE I by uncompetitive mechanism and a direct relationship between α-helix structure and IC50% value was obtained (r = 0.9127). TEAC and cooper chelating activity from GHE 6.5 were the highest and directly correlated with MH peptides. GHE 9.0 had high carotene bleaching inhibition (47.5 ± 0.3%) and reducing power activity (163.1 ± 2.9 mg S₂O₃^2 − equivalent g^− 1 protein), which were directly related to disulfide bonds content of peptides (r = 0.9982 and 0.9216, respectively). pH was a good alternative to select bioactive peptides from wheat gluten hydrolysate.     

Enzymatic Production of Ethanol from Cassava Starch Using Two Strains of Saccharomyces cerevisiae

Cassava starch from TMS 30572 and Idileru were hydrolyzed with α-amylase and amylo-glucosidase before fermentation using two strains of Saccharomyces cerevisiae from palm wine and bakers’ yeast. The per cent yield of sugars and total dissolved solids were 66 % and 26% respectively while pH was 7. Spectrophotometric measurement of the cell growth revealed steady but insignificant (p ≤ 0.05) increase in cell concentrations up to 48 h fermentation time with a gradual decline by 72 h. Saccharomyces cerevisiae strain from palm wine grew best on TMS 30572 hydrolysate at 20% sugar concentration (optical density 0.663; fermentation time 48 h) while on Idileru hydrolysate it grew best at 25% (optical density 0.698; fermentation time 60 h). The pH values obtained from the fermenting hydrolysates for both yeast strains declined gradually as the fermentation progressed with the lowest pH values (3.01 for S. cerevisiae from palm wine; 3.06 for S. cerevisiae from bakers’ yeast) obtained for TMS 30572 cassava variety at 25% sugar concentration. Changes in pH were significant (p ≤ 0.05). The Saccharomyces cerevisiae strain from palm-wine had a higher conversion of available sugar into ethanol. The yield of ethanol was found to vary but the highest ethanol concentration obtained was 5.3% at 10% initial sugar concentration, which gave a sugar conversion efficiency of 37.3%. The results obtained suggest that Saccharomyces cerevisiae strains from sources other than those used conventionally can serve as good substitutes for bio-conversion processes in the industrial production of ethanol.     

Antioxidant activity of Bupleurum kaoi Liu (Chao et Chuang) fractions fractionated by supercritical CO2

Bupleurum kaoi Liu was mixed with ethanol at a ratio of 1:4 (v/w) for 24 h to yield ethanol extract. Extract was further fractionated using supercritical CO₂ (SC-CO₂) under the following operating conditions: 40°C and a pressure of 20, 15, 10 or 5 MPa into R, F1, F2 or F3 fractions, respectively. To assess the selectivity of the fractionation, four fractions were characterized in terms of total phenol contents, the antioxidant abilities and the antioxidant mechanisms. Experimental results indicated that fractionation altered the composition distributions and the antioxidant activities, including antioxidant ability, reducing power and the scavenging capacity of DPPH, superoxide, and hydroxyl radicals. The antioxidant activities increased with fraction concentrations. The scavenging effect on DPPH of B. kaoi L. fractions at 10 g/l was R (53%), F1 (65%), F2 (71%), and F3 (76%), respectively. At a concentration of 5 g/l, all fractions can inhibit the O₂·^—formation by over 50%. Fractions R, F2 and F3 at concentrations of 3 g/l can trap over 50% of the OH groups. Notably, this in vitro study of antioxidant effects demonstrated that antioxidant activities were correlated well with the contents of phenol compounds. F3 fraction, contained the highest levels of total phenol contents, was the best inhibitor of lipid peroxidation and scavengers of DPPH, O₂·^— and ·OH radicals.     

Formation of carcinogenic 4(5)-methylimidazole in caramel model systems: A role of sulphite

Aqueous caramel model systems consisted the d-glucose/NH₃/sulphite were heated at 100 °C for 2 h and amounts of carcinogenic 4(5)-methylimidazole (4-MI) formed were determined. The amount formed ranged from 7.0 to 155.0 ppm. A system with 0.1 M sulphite yielded the greatest amount of 4-MI, which was 54% more than that yielded from a system without sulphite. When the amount of sulphite increased over 0.1 M, the amount of 4-MI reduced. The greatest reduction was achieved with 0.2 M sulphite by 68% compared to 0 M sulphite, suggesting that sulphite plays an important role in the formation of carcinogenic 4-MI in caramel colour. Also, a system with 0.1 M sulphite yielded the most intense caramel colour but the other levels of sulphite did not change the colour intensity significantly. Sulphite contributed slightly to the level of flavour chemicals evaluated using pyrazine formation. The results suggest that sulphite addition at appropriate amount reduces 4-MI formation in caramel colour without sacrificing flavour and colour formation.     

Phenolics,Antiradical Assay and Cytotoxicity of Processed Mango (Mangifera indica) and Bush Mango (Irvingia gabonensis) Kernels

Phenolic constituents (total phenols, flavonoids, tannins, and anthocyanins), comparative antiradical potency and cytotoxicity of processed mango (Mangifera indica) kernel (PMK), processed bush mango (Irvingia gabonensis) kernel (PBMK) and their mixture (MKK) at 50:50 were evaluated. Antiradical assay of the samples was conducted using three different methodologies (lipid peroxidation, nitric oxide and ferric reducing anti-oxidant power (FRAP)). The three samples contained negligible amounts of anthocyanins (< 0.67 ng/g) compared with the other constituents (1.4 to 2.2 mg/g), largely of gallotannins and flavonoids. However, PBMK had the least flavonoid content, averaging 43%. Due to relative sensitivity of assay techniques to phenolic composition of sample extracts, results from FRAP assay favourably complemented those of another technique to give better reflection of sample’s radical scavenging capacity. Mean inhibitory concentration (IC₅₀) values obtained, showed that the three samples had higher antioxidant capacity than reference quercetin. Similarly, the mean lethal concentration (LC₅₀) values obtained from cytotoxicity assay indicated that the phenolic acid and flavonoid content of the three processed kernel samples were more tolerable physiologically compared with reference dichromate. Both observations were statistically significant (p < 0.05). Processed kernels of mango (Mangifera indica) (PMK) and bush mango (Irvingiagabonensis) (PBMK), therefore, could find application as neutraceuticals and antimicrobials.