In vitro study on antioxidant activities of peanut protein hydrolysate

Peanut protein was hydrolysed with a commercial protease, Alcalase 2.4L, and the resulting hydrolysate was investigated for its antioxidant activities, including the ability to inhibit the autoxidation of linoleic acid, the scavenging effect on the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical, the reducing power and the inhibition of liver lipid oxidation. As compared with the peanut protein, peanut protein hydrolysate showed strong inhibition of the autoxidation of linoleic acid, to scavenge DPPH free radical and showed strong reducing power. Moreover, peanut protein hydrolysate also displayed noticeable inhibition of liver lipid autoxidation and lipid oxidation induced by H₂O₂ or Fe²⁺ in vitro. All these effects of the sample were concentration‐dependent. These results suggest that peanut protein hydrolysate could be a suitable natural antioxidant and may be a health food for humans. Copyright © 2006 Society of Chemical Industry     

Intake of aflatoxins through the consumption of peanut products in Brazil

To estimate daily intake of aflatoxins from peanut products consumed by the population of Paraná State (Brazil), 100 samples of peanut products were collected between July 2006 and April 2007. Aflatoxins were determined by an HPLC method with fluorescence detection. There was a 50% occurrence of aflatoxins (B₁, B₂, G₁ and G₂) in concentrations ranging from 0.5 to 113?ng?g^?1, with 13 samples with levels above 20?ng?g^?1. Intake was calculated for average and high adult consumers of peanut products and it was compared with provisional maximum tolerable daily intake (PMTDI). The estimated probable daily intake (PDI) for aflatoxin B₁ (AFB₁) varied from 0.6 to 10.4?ng?kg^?1?bw?day^?1, exceeding the PMTDI of 0.4?ng?kg^?1?bw?day^?1 for carriers of hepatitis B virus.     

Enzymatic treatment of peanut kernels to reduce allergen levels

This study investigated the use of enzymatic treatment to reduce peanut allergens in peanut kernels as affected by processing conditions. Two major peanut allergens, Ara h 1 and Ara h 2, were used as indicators of process effectiveness. Enzymatic treatment effectively reduced Ara h 1 and Ara h 2 in roasted peanut kernels by up to 100% under optimal conditions. For instance, treatment of roasted peanut kernels with α-chymotrypsin and trypsin for 1–3 h significantly increased the solubility of peanut protein while reducing Ara h 1 and Ara h 2 in peanut kernel extracts by 100% and 98%, respectively, based on ELISA readings. Ara h 1 and Ara h 2 levels in peanut protein extracts were inversely correlated with protein solubility in roasted peanut. Blanching of kernels enhanced the effectiveness of enzyme treatment in roasted peanuts but not in raw peanuts. The optimal concentration of enzyme was determined by response surface to be in the range of 0.1–0.2%. No consistent results were obtained for raw peanut kernels since Ara h 1 and Ara h 2 increased in peanut protein extracts under some treatment conditions and decreased in others.     

Determination of aflatoxins in peanut butter and sesame samples using high-performance liquid chromatography method

In this study, total number of samples analysed were 20 packages of sesame and 20 cans of peanut butter, which were collected from Ankara local markets, Turkey. Extraction and determination of aflatoxins have been made by immunoaffinity column technique and high-performance liquid chromatography (HPLC) method. Mean levels (±SE) of aflatoxins B₁, B₂, G₁ were found to be 15.756±3.129 ng/g, 1.232±0.244 ng/g and 9.689±1.005 ng/g, respectively in peanut butter samples. Regarding the sesame samples, mean level of aflatoxin G₁ was found to be 0.754±0.213 ng/g. Our data revealed that while aflatoxin levels found in sesame samples were within the Turkish Food Codex (TFC) values, for peanut butter samples, they were higher than the TFC values.     

Insights into proteolytic processing of the major peanut allergen Ara h 2 by endogenous peanut proteases

BACKGROUND: The major peanut allergens are Ara h 1, Ara h 2 and Ara h 6. Proteolytic processing has been shown to be required for the maturation process of Ara h 6. The aim of this study was to examine whether Ara h 2 undergoes proteolytic processing and, if so, whether proteolytic processing influences its ability to bind human immunoglobulin E (IgE). RESULTS: Ara h 2 isolated from peanut extract under conditions of protease inhibition revealed a single additional peak for its two known isoforms (Ara h 2.01 and Ara h 2.02), corresponding to a C‐terminally truncated form lacking a dipeptide (RY). Ara h 2 isolated in the absence of protease inhibition, however, yielded two additional peaks, identified as C‐terminally truncated forms lacking either a dipeptide (RY) or a single tyrosine residue. The IgE‐binding capacity of the Ara h 2 truncated forms was not altered. CONCLUSION: Ara h 2 undergoes proteolytic processing by peanut proteases that involves C‐terminal removal of a dipeptide. Hence Ara h 2 isolated from peanut extract is a complex mixture of two isoforms expressed by different genes, Ara h 2.01 and Ara h 2.02, as well as truncated forms generated by the proteolytic processing of these isoforms. Copyright © 2010 Society of Chemical Industry     

Enzymatic treatment of peanut butter to reduce the concentration of major peanut allergens

This study investigated the effects of enzymatic treatment of peanut butter on two‐major peanut allergens (Ara h 1 and Ara h 2). Home‐made and commercial peanut butter samples were treated with alpha‐chymotrypsin, trypsin or the combination of these enzymes and incubated at room temperature for 24 h or at 37 °C for 3 h. Treated peanut butter samples were sampled weekly for evaluation of total soluble proteins and extractable Ara h 1/Ara h 2. Data show that 1:1 alpha‐chymotrypsin: trypsin at 0.04% of enzyme‐to‐peanut butter ratio resulted in near complete reduction of extractable Ara h 1 and Ara h 2 respectively. Treatment of peanut butter with a combination of trypsin and alpha‐chymotrypsin resulted in a decrease in IgE‐binding, suggesting that enzymatic treatment has the potential to reduce the allergenicity. However, clinical tests are needed to confirm any reduction in allergenic potential. The amount of water used to disperse enzyme did not have significant effect on allergen reduction but affected the consistency and colour of treated products, especially when the amount of water added was above 5% of peanut butter weight.     

Reduction of fumonisin B₁ in corn grits by twin-screw extrusion

Abstract: This study was designed to investigate the fate of fumonisins in flaking corn grits during twin‐screw extrusion by measuring fumonisin B₁ (FB₁) and its analogs with a mass balance approach. Food grade corn grits and 2 batches of grits contaminated with FB₁ at 10 and 50 μg/g by Fusarium verticillioides M‐2552 were processed with or without glucose supplementation (10%, w/w) with a twin‐screw extruder. Extrusion reduced FB₁ in contaminated grits by 64% to 72% without glucose and 89% to 94% with added glucose. In addition, extrusion alone resulted in 26% to 73% reduction in the levels of fumonisin B₂ and fumonisin B₃, while levels of both mycotoxins were reduced by >89% in extruded corn grits containing 10% glucose. Mass balance analysis showed that 38% to 46% of the FB₁ species detected in corn extruded with glucose was N‐(deoxy‐D‐fructos‐1‐yl)‐FB₁, while 23% to 37% of FB₁ species detected in extruded corn grits with and without added glucose was bound to the matrix. It was also found that the hydrolyzed form of FB₁ was a minor species in extruded corn grits with or without added glucose, representing <15% of the total FB₁ species present. Less than 46% of FB₁ originally present in corn grits could be detected in the fumonisin analogues measured in this study. Research is needed to identify the reaction products resulting from extrusion processing of fumonisin‐contaminated corn products. Practical Application: Twin‐screw extrusion is widely used in food industry for its versatility. This technology may reduce the level of fumonisins in corn particularly with added glucose.     

Effect of selenium fortification during sprouting of peanut seeds receiving HVEF and selenium soaking combination on yield,selenium and resveratrol contents,anti-oxidative properties,and microbial control

Selenium (Se) is essential for human nutrition as it involves many biological functions. In this study, three seed treatments (water soaking, high-voltage electric field (HVEF), HVEF and water soaking), and two Se fortification treatments (Se soaking with Se fortification during sprouting and HVEF plus Se soaking with Se fortification during sprouting) were used to examine their effects on peanut seed germination, Se contents and microbial loads on 8-days-old peanut sprouts. The results indicated that the best treatment for enhancing germination (99.6%), increasing the sprout's total Se and resveratrol contents (61.32 and 46.32 μg g ⁻¹ , respectively) was HVEF plus Se soaking in combination with Se fortification. It also reduced the microbial loads to <3 log CFU g⁻¹ FW on the resultant 8-days-old peanut sprouts. Thus, the treatment of HVEF and Se soaking combination with Se fortification can be used to produce Se-fortified peanut sprouts with improved nutritional quality and microbial control.     

Effect of cold plasma treatment on the antigenicity of peanut allergen Ara h 1

The objective of this study was to investigate the effects of cold atmospheric plasma on the antigenicity of protein Ara h 1. Dry, defatted peanut flour (DPF), whole peanut (WP) were subjected to cold atmospheric plasma at voltage of 80 kV for different treatment durations (0, 15, 30, 45 and 60 min). The allergen samples were analyzed using SDS-PAGE, immunoblot and competitive ELISA. Furthermore, the secondary structure was examined using circular dichroism. SDS-PAGE results revealed no change in the protein intensity bands corresponding to Ara h 1 for both DPF and WP. Competitive ELISA of samples showed a reduction in antigenicity up to 43% for DPF and 9.3% for WP. Circular dichroism studies revealed modifications in secondary structure induced by plasma reactive species.Industrial relevanceCold plasma has emerged as a novel processing technique. This study provides evidence for reduction of antigenicity of Ara h1 in peanuts using cold plasma. This study also demonstrated the plasma-induced changes in protein structure at high treatment duration. The work described in this research is relevant to the processing of cereal grains and legumes wherein allergenicity is a major concern. This results provide the basis for possible industrial implementation.     

Photodegradation of Aflatoxin B<Subscript>1</Subscript> in peanut oil

A photodegradation study of aflatoxin B₁ (AFB₁) in peanut oil was performed under UV irradiation at different AFB₁ initial concentrations and UV irradiation intensities. The UV intensity and the irradiation duration on the AFB₁ photodegradation ratio is more effective, when compared with AFB₁ initial concentration, and AFB₁ with initial concentration of 2 mg/kg can be degraded thoroughly within 30 min under the intensity of 800 μw/cm². The photodegradation of AFB₁ between the selected ranges of concentrations was proved to follow first-order reaction kinetics well (R ² ≥ 0.99). The Ames test, employing Salmonella typhimurium tester strains TA98 and TA100, was employed to evaluate the residual toxicity of the AFB₁ subproducts in peanut oil, and the results indicated that the mutagenic activity of UV-treated samples (800 μw/cm² × 30 min) was completely lost compared with that of untreated samples, providing clues to the assessment of safety issues of UV method applied in AFB₁ decontamination.     

Safety evaluation of aflatoxin B1 in peanut oil after ultraviolet irradiation detoxification in a photodegradation reactor

The high incidence of aflatoxin B₁ (AFB₁) in peanut oil has caused wide public concern in the world. Many studies have verified that ultraviolet (UV) irradiation can degrade AFB₁ in foods. A new photodegradation reactor has been developed to study the photodegradation efficiency of AFB₁ in peanut oil, and the safety of peanut oil was evaluated after UV irradiation detoxification based on the mutagenicity of Salmonella typhimurium tester strains and cytotoxicity of HepG2 cells. The results showed that AFB₁ in peanut oil could be decomposed efficiently using the photodegradation reactor. AFB₁ was decreased from 51.96 ± 4.24 to 7.23 ± 0.59 μg kg^?1 in 10 min and reduced by 86.08% compared with that of the negative control. The residual AFB₁ in peanut oil was far less than the limit level set by Chinese government (20 μg kg^?1). The Ames test and cell viability assay revealed that 10 min of UV irradiation reduced significantly the toxicity of AFB₁ in peanut oil. All the results suggest that the deleterious effects of AFB₁ can be highly reduced by UV irradiation in the photodegradation reactor, and the reactor can be applied in a large scale in detoxification of AFB₁ in peanut oil in the oil industry.     

Optimizing microencapsulation of peanut sprout extract by response surface methodology

This study was carried out to optimize conditions for peanut sprout extract microencapsulation by response surface methodology (RSM). The coating materials of microencapsulation were medium-chain triacylglycerol (MCT) for primary emulsion, and whey protein concentrates (WPC), maltodextrin (MD) and gum Arabic (AG) for secondary emulsion. The yield of microencapsulation of peanut sprout extract was investigated with respect to four variables (ratio of core and coating materials, concentration of primary emulsifier, ratio of W/O emulsion and secondary coating materials and concentration of secondary emulsifier) in RSM. The optimal conditions for microencapsulation of peanut sprout extract were 1:2 as the ratio of core material to coating material, 1.25% (w/v) of primary emulsifier concentration, 1:1.23 as W/O emulsion to secondary coating material, 1.21% (w/v) as secondary emulsifier concentration and 30% (w/w) as WPC concentration for spray drying. In conclusion, the microencapsulation of peanut sprout extract under the optimized conditions by RSM ensures the smaller size (3–7 μm) of microcapsules with the highest yield reaching to 98.74%.     

Reduction of Aspergillus spp. and aflatoxins in peanut sauce processing by oil-less frying of chilli powder and retort processing

ABSTRACT

Among the many roles played by small and medium enterprises (SMEs) in the food industry is the production of heritage foods such as peanut sauce. Unfortunately, the safety of peanut sauce is not always assured as the processing line is not controlled. Peanut sauce is usually made of peanuts and chilli, and these commodities are normally contaminated with Aspergillus spp. and aflatoxins (AFs). Hence, the objective of this study was to evaluate the practices related to reduction of AF hazard and the effect of interventions in peanut sauce processing. Peanut samples were collected from each step of peanut sauce processing from a small peanut sauce company according to four designs: (1) control; (2) oil-less frying of chilli powder; (3) addition of retort processing; and (4) combination of oil-less frying of chilli powder and retort processing. Oil-less frying of chilli powder (Design 2) reduced total AFs by 33–41%, retort processing (Design 3) reduced total AFs by 49%, while combination of these two thermal processes (Design 4) significantly reduced total AFs, by 57%. The present work demonstrated that Design 4 yielded the highest reduction of total AFs and is therefore recommended to be employed by SME companies.     

Degradation of aflatoxin B1 in peanut meal by electron beam irradiation

The effects and safety of electron beam irradiation (EBI) treatment on the detoxification of aflatoxin B₁ (AFB₁) in the peanut meal were evaluated in this article. The AFB₁ degradation was predominantly affected by both initial AFB₁ and water concentrations. The degradation of AFB₁ in the selected concentrations (0.5–5 ppm) was proven to follow pseudo first-order reaction kinetics (R² > 0.95). The AFB₁ degradation was faster when the initial concentration was 5 ppm and the moisture content was 21.47%, in comparison with the initial concentration of 1 ppm and 0.5 ppm and the moisture content of 14.32% and 8.74%, respectively. The Ames and cytotoxicity tests were employed to evaluate the residual toxicity of EBI-treated peanut meal. The mutagenic activity of EB-treated samples was completely lost compared with that of untreated samples and the degradation products in peanut meal has almost no cell toxicity.     

Minimal effects of high-pressure treatment on Salmonella enterica serovar Typhimurium inoculated into peanut butter and peanut products

About 1.2 billion pounds of peanut butter are consumed annually in the United States. In 2008 to 2009, an outbreak involving Salmonella Typhimurium in peanut butter led to a recall of over 3900 products by over 200 companies. More than 700 people became sick, 100 were hospitalized, and 9 people died from this outbreak. This study examines the efficacy of high-pressure processing (HPP) to decrease S. Typhimurium American Type Culture Collection (ATCC) 53647 inoculated into peanut butter and model systems. The viability of S. Typhimurium in peanut butter stored at room temperature was investigated. A culture of S. Typhimurium (6.88 log CFU/g) was inoculated into peanut butter. Following 28 d at 20 °C there was a 1.23-log reduction. Approximately 10(6) to 10(7) CFU/g S. Typhimurium were inoculated into 4 brands of peanut butter, 3 natural peanut butters and peanut flour slurries at 2, 5, and 10% peanut flour protein in peanut oil and in distilled water. All were treated at 600 MPa for 5 min at 45 °C. While significant differences were found between natural peanut butter and peanut protein mixtures, the reduction was <1.0 log. The peanut flour/oil mixtures had a 1.7, 1.6, and 1.0-log reduction from HPP (2, 5, and 10% protein, respectively) whereas peanut flour/water mixtures had a 6.7-log reduction for all protein levels. Oil had a protective effect indicating HPP may not help the microbial safety of water-in-oil food emulsions including peanut butter. Practical Application: There have been multiple outbreaks of foodborne illness involving peanut butter products. This study looks at the potential use of high-pressure processing to reduce the bacteria that may be in peanut butter.     

Ochratoxin A and the occurrence of ochratoxin A‐producing black aspergilli in stored peanut seeds from Córdoba,Argentina

Since there is no available information about the natural occurrence of ochratoxin‐producing fungi and ochratoxin A (OTA) in peanut seeds in Argentina, the aims of this work were to isolate and identify Aspergillus section Nigri and to evaluate the natural occurrence of OTA in stored peanut seeds. Likewise, the capacity to produce OTA by Aspergillus section Nigri was studied. Forty‐seven samples of peanut seeds were obtained from a storage plant in the south of Córdoba Province, Argentina. Each sample of 100 seeds was surface‐disinfected and plated onto a dichloran 18% glycerol agar (DG18). OTA was detected by HPLC. The production of OTA in strains belonging to section Nigri was tested in YES medium (2% yeast extract, 15% sucrose). Aspergillus spp., the most frequent mould, occurred in 100% of samples, followed by Penicillium spp. (87%) and Eurotium spp. (6.4%). A. flavus was isolated in 100% of the samples, followed by A. niger var. niger, A. niger var. awamori and A. carbonarius at a lower frequency, 89%, 68% and 4%, respectively. OTA was found in 32% of the peanut seed samples, with mean levels ranging from 0.5 to 170 ng g^?1. The mean recovery of the method used was 85 ± 2%. Forty‐three isolates (27%) of Aspergillus section Nigri, were found to be OTA producing strains. The highest percentage of ochratoxigenic strains (57%) was found within the A. carbonarius ssp. These results indicate a human exposure to OTA in Argentina through the ingestion of peanut seeds and peanut products. Copyright © 2006 Society of Chemical Industry     

Emulsifying properties of the transglutaminase-treated crosslinked product between peanut protein and fish (Decapterus maruadsi) protein hydrolysates

BACKGROUND: Defatted peanut meal, a protein‐rich by‐product from the oil extraction industry, is underutilised owing to its inferior functional properties. In this study, transglutaminase (TGase) crosslinking and proteolysis were used to improve the emulsifying properties of peanut protein isolate (PPI) extracted from the meal. PPI and PPI hydrolysate (PPIH) were conjugated separately with fish (Decapterus maruadsi) protein hydrolysate (DPH), catalysed by TGase to obtain improvements in the emulsifying properties. RESULTS: Analyses by electrophoresis and high‐performance liquid chromatography indicated that polymers were formed in all TGase‐treated samples. In emulsions of PPIH, PPI‐DPH and PPIH‐DPH the volume/surface average particle diameter (d₃₂), creaming and instability phenomenon were decreased and the zeta‐potential was increased after TGase treatment, showing improved emulsifying activity and emulsion stability. In the case of PPI, TGase treatment had no effect on the emulsifying activity, but the emulsion stability of TGase‐treated PPI was improved. CONCLUSION: The study showed that TGase crosslinking and proteolysis could improve the emulsifying properties of PPI, while proteolysis followed by TGase crosslinking proved more efficient. The emulsifying properties of the heterologous protein systems of PPI‐DPH and PPIH‐DPH were also improved by TGase treatment. Copyright © 2010 Society of Chemical Industry     

Efficiency and safety evaluation of photodegradation of Aflatoxin B1 on peanut surface

A photodegradation study of Aflatoxin B₁ (AFB₁) on peanut surface was performed under UV irradiation at different UV irradiation intensities. With an initial quantity of 10 ng of AFB_1, it can be degraded thoroughly within 80 min under the intensity of 800 μw cm^?2. The photodegradation pathway of AFB₁ on the peanut surface was proposed. Mutagenesis and cytotoxicity were assessed after exposure to different concentrations of AFB₁ and the mixtures of photodegradation products on the peanut surface. The results of the Ames and in vitro cytotoxicity assay, providing clues to the assessment of safety issues of UV method applied in AFB₁ decontamination, indicate that photodegradation products on the peanut surface has no toxicity, which can be explained by the differences in the chemical nature of the test compounds before and after UV irradiation.     

Optimization of extraction of phenolic antioxidants from peanut skins

This work was conducted to optimize the extraction conditions for the best recovery of antioxidant compounds from peanut skins. The extracts from the peanut skins were obtained by different extraction methods. The extraction conditions were: different ethanol proportions as the solvent (0, 30, 50, 70 and 96% v/v in distilled water), different peanut skin particle sizes (0–1, 1–2 and 2–10 mm and non‐crushed skins), different proportions of solvent/skins (20, 30, 40, 50 and 60 ml g^?1), different extraction times (by maceration and shaking) and different numbers of extractions. The different extracts obtained under different extraction conditions were compared with special regard to yield, total phenolic compounds and radical scavenging activity. The results showed that the best delivery of phenolic compounds was reached using 70% ethanol, non‐crushed peanut skins, ratio of solvent/solid of 20 ml g^?1, at 10 min shaking and three extractions. The maximum yield of 0.118 g g^?1 was recorded for phenolic compounds when extracted at the optimum conditions. Copyright © 2004 Society of Chemical Industry     

Reduction of aflatoxins in peanut meal by extrusion cooking in the presence of nucleophiles

This study explored the feasibility of degrading aflatoxins in contaminated peanut meal by extruding in the presence of calcium chloride with lysine and methylamine. A 2 × 2 × 3 experiment (moisture, pH and nucleophile) was designed to screen for a nucleophile to use in a study of extrusion conditions to degrade aflatoxins in peanut meal. The nucleophile was mixed with peanut meal at 2 g/100 g protein level and the samples “spiked” with aflatoxin standards. They were extruded using a single screw extruder, and aflatoxins quantified by HPLC.The presence of calcium chloride impeded the degradation of aflatoxins by extrusion. However, methylamine and lysine showed comparable efficacies to mediate aflatoxin reduction. There were significant (p ≤ 0.05) interactions between moisture and pH, as well as moisture and temperature. Contour plots from regression models (R² = 0.85) showed a bimodal effect of moisture on aflatoxin degradation. Extrusion cooking reduced aflatoxins from an initial 417.72 μg/kg to 66.87 μg/kg (i.e. 84% reduction) in the peanut meal.