Effects of onion on physicochemical properties,lipid oxidation and microbial growth of fresh pork patties

Onions with or without heating (100 °C, 30 min) were extracted with water or methanol, and antioxidant and antimicrobial activities of onion extracts were evaluated. Product characteristics of fresh pork patties containing various onion extracts were measured during refrigerated storage. Water extracts of onions showed higher extraction yield and iron chelating ability than methanol extracts (P < 0.05), whereas, the latter was more effective than the former in phenolic compounds and reducing power (P < 0.05). The addition of onion extracts [water extract from fresh onion (WEFO), methanol extract from heated onion (MEHO) and their combinations (WEFMEHO)] to pork patties decreased redness, increased yellowness, and inhibited lipid peroxidation (P < 0.05). One per cent of WEFMEHO in pork patties had antioxidant activities as effective as butylated hydroxyl toluene (BHT, 0.01%). Redness and yellowness decreased and increased with the addition of onion extract, respectively (P < 0.05).     

Effects of Onion (Allium cepa L.) and Garlic (Allium sativum L.) Essential Oils on the Aspergillus versicolor Growth and Sterigmatocystin Production

Abstract: In the present study the effects of individual and combined essential oils (EOs) extracted from onion (Allium
cepa L.) bulb and garlic (Allium sativum L.) clove on the growth of Aspergillus versicolor and sterigmatocystin (STC) production were investigated. The EOs obtained by hydrodistillation were analyzed by GC/MS. Twenty one compounds were identified in onion EO. The major components were: dimethyl‐trisulfide (16.64%), methyl‐propyl‐trisulfide (14.21%), dietil‐1,2,4‐tritiolan (3R,5S‐, 3S,5S‐ and 3R,5R‐ isomers) (13.71%), methyl‐(1‐propenyl)‐disulfide (13.14%), and methyl‐(1‐propenyl)‐trisulfide (13.02%). The major components of garlic EO were diallyl‐trisulfide (33.55%), and diallyl‐disulfide (28.05%). The mycelial growth and the STC production were recorded after 7, 14, and 21 d of the A. versicolor growth in Yeast extract sucrose (YES) broth containing different EOs concentrations. Compared to the garlic EO, the onion EO showed a stronger inhibitory effect on the A. versicolor mycelial growth and STC production. After a 21‐d incubation of fungi 0.05 and 0.11 μg/mL of onion EO and 0.11 μg/mL of garlic EO completely inhibited the A. versicolor mycelial growth and mycotoxins biosynthesis. The combination of EOs of onion (75%) and garlic (25%) had a synergistic effect on growth inhibition of A. versicolor and STC production. Practical Application: A substitution of synthetic preservatives with natural antimicrobial compounds in food safety to control fungal contamination and mycotoxin production.     

Evaluation of pre‐heating and extraction solvents in antioxidant and antimicrobial activities of garlic,and their application in fresh pork patties

The objectives of this study were to screen the optimum conditions for antioxidant and antimicrobial activities of garlic as affected by pre‐heating and different extraction solvents, and to evaluate the antioxidant and antimicrobial effects of these extracts in ground meat during refrigerated storage. Methanol extracted garlic had a greater total phenolic content, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH)‐radical scavenging activity and reducing power than water extracted one (P < 0.05), whereas the latter had a greater yield and iron chelating ability than the former (P < 0.05). Moreover, water extract from fresh garlic (WEFG) and methanol extract from heated garlic (MEHG) produced an inhibition zone against Escherichia coli O157:H7 and Listeria monocytogenes. The addition of garlic extracts (WEFG, MEHG and their combinations WEFMEHG)) to pork patties decreased the pH, hunter a values (redness), thiobarbituric acid substances values and the number of total plate count and Enterobacteriaceae (P < 0.05), while the hunter b values (yellowness) increased (P < 0.05). Results of this study indicated that the use of the garlic extracts was able to control lipid oxidation and microbial growth in pork patties.     

Inhibition of Growth and Germination of C. botulinum 33A, 40B, and 1623E by Essential Oil of Spices

Effects of clove, thyme, black pepper, pimenta, origanum, garlic, onion, and cinnamon oils on growth and germination of Clostridium botulinum types 33A, 40B, and 1623E were studied. At 200 ppm, ail oils highly inhibited growth of C. botulinum 33A, 40B, and 1623E. At 10 ppm, inhibitory activity of most oils diminished. By activity on C. botulinum growth, oils could be divided into three categories: (1) very active: cinnamon, origanum, and clove; (2) active: pimenta, and thyme; (3) least active: garlic, onion, and black pepper. Effectiveness on germination was quite different. At 150 and 200 ppm all oils totally prevented germination. At 10 ppm garlic and onion showed higher activity than the others. Spores of 33A were more sensitive than 40B and 1623E.     

Physicochemical Properties,and Antioxidant and Antimicrobial Effects of Garlic and Onion Powder in Fresh Pork Belly and Loin during Refrigerated Storage

ABSTRACT: Pork loin and belly cuts were pumped to 110% of their original weight with solutions containing 5% of various ingredients (sodium ascorbate, garlic, and onion powder), and evaluated the physicochemical properties, and antioxidant and antimicrobial activities during refrigerated storage at 8 °C. The addition of garlic and onion powder tended to increase redness (a) and yellowness (b) in both the belly lean and loin with the exception of a few cases. Free fatty acid values in both pork belly and loin cuts were reduced with the addition of these ingredients, as compared to the control. Significant differences in peroxide values were observed in sodium ascorbate and garlic‐injected belly, and in sodium ascorbate and onion‐injected loin, as compared to the control. Thiobarbituric acid reactive substance values in the pork belly with garlic or onion powder were significantly lower than in the belly without these ingredients or with sodium ascorbate (P < 0.05). Total plate counts were lower in both the belly and loin containing garlic and onion powder, as compared to the control. In both the belly and loin cuts, the content of oxidative products (volatile compounds) was reduced with the addition of garlic and onion powder, particularly the aldehydes (hexanal). Overall, garlic and onion in enhanced meats showed an antioxidant activity as effective as that of sodium ascorbate and also an antimicrobial effect to inhibit the growth of total bacteria and Enterobacteriaceae.     

Degradation of condensed tannins by rumen microbes exposed to quebracho tannins (QT) in rumen simulation technique (RUSITEC) and effects of QT on fermentative processes in the RUSITEC

In an earlier study it was observed that the rumen microbes from cattle which had never consumed tannin-containing diets do not have enzymes for degrading condensed tannins. In this study, rumen microbes were exposed to small amounts of quebracho tannins for 8 days using a rumen simulation technique (RUSITEC). The levels maintained in the RUSITEC were 0.1, 0.2 and 0.4 mg of the spray-dried quebracho powder (SDQT) per ml of the medium. After 8 days of tannin exposure, the liquor containing ‘exposed/adapted’ microbes from RUSITEC was incubated for 40 h without and with purified tannins of quebracho and Dichostachys cinerea leaves in in vitro gas method. There was no degradation of condensed tannins. The enzymes for degradation of condensed tannins were not induced in rumen microbes by exposure to different concentrations of tannins for 8 days in the RUSITEC. In the RUSITEC, SDQT significantly reduced the number of total protozoa, entodiniomorphs and holotrichs; effect was higher on holotrichs. There was no significant change in the levels of short chain fatty acid but the molar proportion of propionate was significantly higher and of butyrate significantly lower at 0.4 mg SDQT ml^?1. Significantly lower levels of ammonia in the medium was also observed on injection of tannins. Microbial mass production, calculated using ¹⁵N incorporation, was similar at 0.1 and 0.2 mg SDQT ml^?1 but significantly lower (13%) at 0.4 mg SDQT ml^?1. The dry matter digestibility of the feed (80% hay and 20% barley) was not significantly affected by SDQT.     

Control of Some Filamentous Fungi and Yeasts by Dehydrated Allium Extracts

The antifungal activities of dehydrated garlic (Allium sativum L.), onion (Allium cepa L.) and leek (Allium porrum L.) against Aspergillus niger, Fusarium oxysporum, Candida albicans ATCC 10231 and Metschnikowia fructicola were investigated. Inhibition activities of the ethyl alcohol or acetone extracts of dehydrated Allium species were studied by disc-diffusion and broth dilution methods. The Minimum Inhibitory Concentration (MIC) and the Minimum Fungicidal Concentration (MFC) were found in the range of 75 and 100 mg/mL (w/v). Ethyl alcohol extracts of dehydrated onion (Allium cepa L.) in the range of 75 and 175 mg/mL were determined as the most inhibitory MIC and MFC for A. niger, F. oxysporum and C. albicans respectively. The extracts possess antifungal activity against some of the tested filamentous fungi and yeasts at various concentrations.     

Control of Some Filamentous Fungi and Yeasts by Dehydrated Allium Extracts

The antifungal activities of dehydrated garlic (Allium sativum L.), onion (Allium cepa L.) and leek (Allium porrum L.) against Aspergillus niger, Fusarium oxysporum, Candida albicans ATCC 10231 and Metschnikowia fructicola were investigated. Inhibition activities of the ethyl alcohol or acetone extracts of dehydrated Allium species were studied by disc-diffusion and broth dilution methods. The Minimum Inhibitory Concentration (MIC) and the Minimum Fungicidal Concentration (MFC) were found in the range of 75 and 100 mg/mL (w/v). Ethyl alcohol extracts of dehydrated onion (Allium cepa L.) in the range of 75 and 175 mg/mL were determined as the most inhibitory MIC and MFC for A. niger, F. oxysporum and C. albicans respectively. The extracts possess antifungal activity against some of the tested filamentous fungi and yeasts at various concentrations. Received: July 8, 2008; accepted: July 30, 2008     

The effects of brined onion extracts on lipid oxidation and sensory quality in refrigerated cooked turkey breast rolls during storage

The effects of brined onion extracts on selected aspects of quality in cooked encased turkey breast rolls were evaluated during refrigerated storage over 7 days. Using the thiobarbituric acid (TBA) assay, a 50% strength juice gave a significant reduction (P < 0.0001) in lipid oxidation in both 100 g and 1 kg rolls relative to controls. Quercetin, the main onion juice antioxidant, was reduced by 65% in freshly cooked 1 kg rolls compared with raw rolls but changed little thereafter in storage. Cook yields were significantly higher for rolls containing added onion extracts than for controls (P < 0.05) but no colour differences were detected using Hunter Lab values (P ? 0.05). A 30-member untrained sensory panel expressed no preference for freshly opened 4 day-stored control or onion extract-supplemented rolls packed in plastic casings but there was a significant preference (P < 0.05) for the onion extract product when 4 mm thick meat slices were stored in air for an additional 24 h.     

Comparison of antioxidant activities of onion and garlic extracts by inhibition of lipid peroxidation and radical scavenging activity

The antioxidant activities of the methanol extracts of selected varieties and parts of garlic and onion were determined by two methods: inhibition of lipid peroxidation induced by tert-butyl hydroperoxide in isolated rat hepatocytes and scavenging activity against diphenylpicrylhydrazyl radical. The total phenolics and the main flavonoids of the hydrolysed onion and garlic samples were also analysed. The antioxidant activities obtained by the two methods were compared. Both methods gave similar antioxidant activities for pure compounds and Allium extracts. However, the radical scavenging method had many benefits compared to the lipid peroxidation method, being easier, cheaper, more specific and reproducible. The radical scavenging activities also correlated positively with the total phenolics of the extracts. Onions had clearly higher radical scavenging activities than garlic, red onion being more active than yellow onion. The skin extracts of onion possessed the highest activities.     

三种蔬菜浸提液对酱菜中亚硝酸盐清除作用的比较研究

采用盐酸萘乙二胺分光光度法测定了大蒜、大葱、洋葱三种蔬菜浸提液在同等条件下对酱菜中亚硝酸盐的清除率。实验结果表明:三种蔬菜浸提液均能有效地清除酱菜中的亚硝酸盐,清除率依次为大蒜(75.09%)>大葱(62.48%)>洋葱(56.41%)。与大葱、洋葱相比,大蒜对酱菜中亚硝酸盐的清除率差异达极显著水平(P<0.01),大葱与洋葱差异达显著水平(P<0.05)。     

Retention of Antioxidant Capacity of Vacuum Microwave Dried Cranberry

ABSTRACT: In this study, cranberries were dried by vacuum-microwave drying (VMD), freeze-drying (FD), or hot air-drying (AD), to compare the effects of different drying processes on both physical changes as well as the retention of bioactive components in dried samples. Total porosity (%) and average pore radius of dehydrated cranberries were greater using VMD compared to FD and AD (P < 0.05). Crude methanol cranberry powdered extracts were fractionated by solid phase extraction (SPE) into organic acid-, total phenolics-, anthocyanin-, or proanthocyanidin-enriched extracts, respectively. The chemical composition of the 60% acidified methanol fractions contained cyanidin-3-galactoside, cyanidin-3-arabinoside, peonidin-3-galactoside, and peonidin-3-arabinoside, as assessed by HPLC. Antioxidant activities of cranberry fractions were measured using chemical ORAC and ABTS methods. The 60% acidified methanol fraction had a significantly higher (P < 0.05) antioxidant potential than the other chemical fractions, which was largely attributed to the relatively higher anthocyanin content. In general, vacuum-microwave drying and freeze-drying resulted in similar retention of anthocyanins and antioxidant activity, which were both relatively higher (P < 0.05) than that recovered from cranberries dried by hot air drying.     

Effect of adding an anaerobic fungal culture isolated from a wild blue bull (Boselophus tragocamelus) to rumen fluid from buffaloes on in vitro fibrolytic enzyme activity,fermentation and degradation of tannins and tannin‐containing Kachnar tree (Bauhinia variegata) leaves and wheat straw

The study investigated the effects of adding an anaerobic fungus (Piromyces sp FNG5; isolated from the faeces of a wild blue bull) to the rumen fluid of buffaloes consuming a basal diet of wheat straw and concentrates on in vitro enzyme activities, fermentation and degradation of tannins and tannin‐rich tree leaves and wheat straw. In experiment 1, strained rumen fluid was incubated for 24 and 48 h, in quadruplicate, with or without fungal culture using condensed tannin‐rich Bauhinia variegata leaves as substrates. In experiment 2, in vitro incubation medium containing wheat straw and different concentrations of added tannic acid (0–1.2 mg mL^?1) were incubated for 48 h, in quadruplicate, with strained buffalo rumen fluid with or without fungal culture. In experiment 3, tolerance of the fungal isolate to tannic acid was tested by estimating fungal growth in pure culture medium containing different concentrations (0–50 g L^?1) of tannic acid. In in vitro studies with Bauhinia variegata tree leaves, addition of the fungal isolate to buffalo strained rumen liquor resulted in significant (P < 0.01) increase in neutral detergent fibre (NDF) digestibility and activities of carboxymethyl cellulase (P < 0.05) and xylanase (P < 0.05) at 24 h fermentation. There was 12.35% increase (P < 0.01) in condensed tannin (CT) degradation on addition of the fungal isolate at 48 h fermentation. In in vitro studies with wheat straw, addition of the fungus caused an increase in apparent digestibility (P < 0.01), true digestibility (P < 0.05), NDF digestibility (P < 0.05), activities of carboxymethyl cellulase (P < 0.001), β‐glucosidase (P < 0.001), xylanase (P < 0.001), acetyl esterase (P < 0.001) and degradation of tannic acid (P < 0.05). Rumen liquor from buffaloes which had never been exposed to tannin‐containing diet had been found to have substantial inherent tannic acid‐degrading ability (degraded 55.3% of added tannic acid within 24 h of fermentation). The fungus could tolerate tannic acid concentration up to 20 g L^?1 in growth medium. The results of this study suggest that introduction of an anaerobic fungal isolate with superior lignocellulolytic activity isolated from the faeces of a wild herbivore may improve fibre digestion from tannin‐containing feeds and degradation of tannins in the rumen of buffaloes. Copyright © 2005 Society of Chemical Industry     

Effects of Essential Oils from Plants on Growth of Food Spoilage Yeasts

Thirty-two essential oils from plants were screened for inhibitory effects on 13 food-spoilage and industrial yeasts. Of these, essential oils of allspice, cinnamon, clove, garlic, onion, oregano, savory, and thyme were most inhibitory. Oils were subsequently tested for their effects on biomass production and pseudomycelium formation of eight genera of yeasts. Garlic oil was a potent inhibitor of yeast growth at concentrations as low as 25 ppm. The oils of onion, oregano and thyme were also strongly inhibitory. Essential oils (100 ppm) had no effect on pseudomycelium production by Candida lipolytica. However, all eight essential oils delayed pseudomycelium formation by Hansenula anomala, whereas six oils stimulated pseudomycelium production by Lodderomyces elongisporus. Cinnamon and clove oils were clearly stimulatory to pseudomycelium production by Saccharomyces cerevisiae.     

Effects of essential oils and oleoresins of plants on ethanol production,respiration and sporulation of yeasts

Ethanol production, respiration, and sporulation of yeasts as effected by essential oils and oleoresins of allspice, cinnamon, clove, garlic, onion, oregano, savory, and thyme were investigated. Essential oils of allspice, cinnamon, and clove had little or no effect on ethanol production by Sacchraromyces cerevisiae. Oils of onion, oregano, savory, and thyme delayed and/or reduced the production of ethanol. Overall, essential oils effectively suppressed ethanol production by Hansenula anomala. At the highest concentrations tested (500 μg/ml), only cinnamon, clove, garlic and thyme oleoresins substantially delayed and/or reduced ethanol production by S. cerevisiae. Most of the essential oils (100 μm/ml) impaired the respiratory activity of S. cerevisiae as evidenced by a reduction in CO₂ production. Thyme oleoresin was the strongest inhibitor. Allspice and garlic oils impaired sporulation by H. anomala. All oils delayed sporulation of Lodderomyces elongisporus).     

Inhibition of lipid oxidation in anchovy oil (Engraulis encrasicholus) enriched emulsions during refrigerated storage

The aim of this study was to produce a functional emulsion product enriched with anchovy (Engraulis encrasicholus) oil. Tomato and garlic extracts were added to perform oxidative stability. Tomato and garlic extracts were added to avoid oxidative degradation in such a product. The plant extracts delayed the formation of primary and secondary oxidation products. The value of conjugated diens (3.07 ± 0.15) was markedly low in the emulsions containing garlic extract at the end of the storage period. The p–Av values of the emulsions treated with the extracts were significantly (P < 0.01) lower than untreated samples. TBARS formation increased slightly, therewithal statistical difference was not observed in the samples treated with garlic extract during the storage. Strong odour and flavour of the garlic suppressed the odour of fish oil. The panellists preferred the flavour, odour and aroma characteristics of the samples treated with the extracts.     

The effect of monensin supplementation of dried grass or barley diets on aspects of propionate metabolism,insulin secretion and lipogenesis in the sheep

The effects of 33 mg kg ^?1 monensin supplementation (+M) of barley (HC) or dried grass (HF) diets on aspects of propionate metabolism, insulin secretion, rumen vitamin B₁₂ synthesis and lipogenesis in sheep were investigated. Monensin had no significant effect on the estimated metabolisable energy intake, or the liveweight gain, but increased the proportion of propionate in rumen volatile fatty acids (VFA), P<0.01 and P<0.05 for HC and HF diets respectively, and increased rumen ammonia concentration, P<0.01 for both diets. Plasma propionate concentrations were increased (P<0.01) with the HC+M diet. Significant increases in adipose tissue and liver-propionyl-CoA carboxylase (P<0.001), a non-significant trend toward increases in fatty acid synthetase and significant increases in malic enzyme (P<0.01), indicated an induction of the pathways of propionate metabolism and lipogenesis; this was also supported by a trend toward increases, or significant increases, in total propionate derived fatty acids (PDFA), branchedchain fatty acids (BCFA) (P<0.01) and 18:1/18:0 ratio (P<0.02) in adipose tissue triacylglycerols of sheep fed the HC+M diet. Dietary monensin did not influence plasma glucose but reduced plasma insulin concentrations with both diets, P<0.001 and P<0.05 for HC and HF diets respectively, possibly due to a direct effect of monensin on insulin secretion. Monensin supplementation led to significant increases (P<0.02) or a trend toward increases in serum vitamin B₁₂, for HC and HF diets respectively, and to significant increases in liver vitamin B₁₂ (P<0.02) for the HF diet.     

Antimicrobial activity of essential oil extracts of various onions (Allium cepa) and garlic (Allium sativum)

Antimicrobial activity of different concentrations (50, 100, 200, 300 and 500 ml/l) of essential oil extracts of three type of onions (green, yellow and red) and garlic against two bacteria, Staphylococcus aureus, Salmomella Enteritidis, and three fungi, Aspergillus niger, Penicillium cyclopium and Fusarium oxysporum, was investigated. The essential oil (EO) extracts of these Allium plants (garlic and onions) exhibited marked antibacterial activity, with garlic showing the highest inhibition and green onion the lowest. Comparatively, 50 and 100 ml/l concentrations of onions extracts were less inhibitory than 200, 300 and 500 ml/l concentrations. However, with garlic extract, high inhibitory activity was observed for all tested concentrations. S. aureus showed less sensitivity towards EO extracts inhibition, however S. Enteritidis was strongly inhibited by red onion and garlic extracts. The fungus F. oxysporum showed the lowest sensitivity towards EO extracts, whereas A. niger and P. cyclopium were significantly inhibited particularly at low concentrations. Conclusively, where seasoning is desired, essential oil extracts of onions and garlic can be used as natural antimicrobial additives for incorporating in various food products.     

Effect of garlic powder on the performance,egg traits and blood parameters of laying hens

This study was conducted to investigate the effects of garlic powder on the performance, egg traits and blood parameters of laying hens. One hundred and sixty‐two SHSY‐type brown layers aged 21 weeks were chosen at random from a large flock. They were allocated to three dietary treatments. Each treatment comprised six replicates of nine layers in groups of three. The diets were supplemented with 0, 5 and 10 g kg^?1 garlic powder. The experimental period lasted 22 weeks. Garlic powder addition did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit, egg yolk weight and serum protein concentration. Egg weight increased (P < 0.01) with garlic powder supplementation. There was a significant (P < 0.01) reduction in egg cholesterol concentration as mg g^?1 yolk when the dietary level of garlic powder was increased from 0 to 10 g kg^?1. Hen serum triglyceride (P < 0.05) and total cholesterol (P < 0.01) concentrations decreased with garlic powder supplementation. This study demonstrated that garlic powder addition increased egg weight and decreased egg yolk cholesterol concentration (mg g^?1 yolk) and serum triglyceride and cholesterol concentrations without adverse effects on performance and egg traits. Copyright © 2006 Society of Chemical Industry     

The effect of supplemental methionine and inorganic sulphate on the ruminal digestion of grass silage in sheep

The effects of an intra-ruminal infusion of a mixture of methionine (7.0 g day^?1) and sodium sulphate (6.7 g day^?1) on the digestion of grass silage were examined in four sheep fitted with cannulas in the rumen and proximal duodenum. There were no significant (P>0.05) effects of the infusion on the ruminal digestion of OM, cellulose or N, or on the concentrations of total or individual VFA in the rumen fluid though the numbers of protozoa in the rumen were reduced (P<0.05). The amounts of total methionine or of bacterial nitrogen reaching the duodenum were not significantly (P>0.05) altered by the infusion and rates of bacterial synthesis were 21 and 23 g N kg^?1 OM (s.e.d. 3.7, P>0.05) apparently digested in the rumen for the control and infusion treatments respectively. The infusion resulted in a significant (P<0.01) increase of 21% in the amount of total long-chain fatty acids at the duodenum. This reflected an increased flow of all fatty acids of chain-length 14:0 and above though more than 80% the response was accounted for by the increased flow of 18:0 and 16:0 acids. It is concluded that the infused supplement stimulated the synthesis of microbial lipid in the rumen.