Detecting internal quality of peanuts during storage using electronic nose responses combined with physicochemical methods.

In this study, the changes in the quality of unshelled peanuts and peanut kernels during storage were analyzed using an electronic nose (e-nose). The physicochemical indexes (acid and peroxide values) of peanut kernels were tested by traditional method as a reference. The storage time of peanut kernels increases from left to right in the cluster analysis plot based on the physicochemical indexes. The "maximum values", "area values", and "70th s values" methods were applied to extract the feature data from the e-nose responses. Principal component analysis (PCA) results indicated that the "70th s values" method produced the most accurate results, furthermore, unshelled peanut and peanut kernel samples presented similar characteristics in the PCA plots; the partial least squares regression (PLSR) results showed that the features of unshelled peanuts and peanut kernels are highly correlated with acid and peroxide values, respectively.

Global risk assessment of aflatoxins in maize and peanuts: are regulatory standards adequately protective?

The aflatoxins are a group of fungal metabolites that contaminate a variety of staple crops, including maize and peanuts, and cause an array of acute and chronic human health effects. Aflatoxin B1 in particular is a potent liver carcinogen, and hepatocellular carcinoma (HCC) risk is multiplicatively higher for individuals exposed to both aflatoxin and chronic infection with hepatitis B virus (HBV). In this work, we sought to answer the question: do current aflatoxin regulatory standards around the world adequately protect human health? Depending upon the level of protection desired, the answer to this question varies. Currently, most nations have a maximum tolerable level of total aflatoxins in maize and peanuts ranging from 4 to 20ng/g. If the level of protection desired is that aflatoxin exposures would not increase lifetime HCC risk by more than 1 in 100,000 cases in the population, then most current regulatory standards are not adequately protective even if enforced, especially in low-income countries where large amounts of maize and peanuts are consumed and HBV prevalence is high. At the protection level of 1 in 10,000 lifetime HCC cases in the population, however, almost all aflatoxin regulations worldwide are adequately protective, with the exception of several nations in Africa and Latin America.

Aflatoxin testing in peanuts: a proficiency assessment scheme for Chinese analytic laboratories.

This national assessment program was established by the China National Accreditation Service for Conformity Assessment (CNAS) to evaluate the aflatoxin-testing proficiency of a cross-section of Chinese laboratories. The Shan Dong Inspection and Quarantine Bureau of China conducted the assessment according to ISO 13528:2005 (E) and the International Harmonized Protocol for Proficiency Testing. The 77 laboratories that participated in the study had either been previously accredited by CNAS or were candidates for CNAS accreditation. The analytic samples for this testing scheme were prepared from naturally contaminated peanuts and diluted to approximately 10 microg/kg for aflatoxin B1 and 18 microg/kg for total aflatoxins. The Ss/sigma p test (with a required result of Ss < or = 0.3 sigma p) was used to evaluate the homogeneity of the test samples; sample stability was confirmed with a t-test. The performance of each laboratory was designated by a z-score that was calculated using robust statistics. The robust mean of the participants' results in this study was nearly coincident with the median. A modified Horwitz equation was used to determine the standard deviation. The study compared analytic results obtained by 5 different methods: high-performance liquid chromatography (LC), enzyme-linked immunosorbent assay, thin-layer chromatography, fluorometry, and LC with tandem mass spectrometry. A satisfactory performance rating required z-scores between -2 and +2 for the target analytes. Of the 73 laboratories that reported results for aflatoxin B1, 66 (90.4%) performed satisfactorily. Of 32 laboratories that reported total aflatoxins (B1 + B2 + G1 + G2), 30 (93.8%) performed satisfactorily. Laboratories whose performance ratings were questionable or unsatisfactory were re-evaluated in a second interlaboratory comparison.

A survey of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and brazil nut kernels received into three Australian nut-processing facilities over a period of 3 years.

There is little information about bacteriological quality of preroasted kernels available in the public domain. An investigation of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into three Australian nut-processing facilities was performed over a period of 3 years. A total of 836 samples were analyzed for aerobic plate count, and 921 samples for Salmonella and Escherichia coli. The 921 samples included 653 peanut, 100 cashew, 60 almond, 60 Brazil nut, and 48 hazelnut kernels. There was no E. coli detected in any sample. Salmonella subsp. II (Fremantle) was detected in one raw almond sample. The aerobic plate count percentages of positive samples with counts above the detection level of the plating method used (100 CFU/g) for peanuts, almonds, cashews, hazelnuts, and Brazil nuts were 84, 78, 74, 50, and 45%, respectively. Of the samples containing more than this detection limit, the means were 4.5, 4.4, 3.1, 2.5, and 3.8 log CFU/g respectively. Although roasted kernel quality was not within the scope of this survey, raw microbial bioload would be expected to reduce on roasting. The bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into nut-processing facilities in Australia does not appear to suggest a public health concern.

Optimization of trans-resveratrol concentration and sensory properties of peanut kernels by slicing and ultrasound treatment, using response surface methodology.

Effect of postharvest stress application by slicing at 0.2, 0.4, and 0.6 cm, exposure to ultrasound (power density of 39.2 mW/cm3) for 4 min at 25 degrees C and subsequent incubation for 24, 36, 42, and 48 h on trans-resveratrol concentrations, and sensory attributes were evaluated using response surface methodology. Peanuts sliced 0.4 and 0.6 cm, exposed to ultrasound, and incubated for 42 h had trans-resveratrol concentrations above 1.0 microg/g, as did all samples incubated for 48 h. The optimized area was bound by peanut size of 0.89, 0.72, and 0.64 and incubation time of 48, 41.5, and 48 h, respectively. Combinations of treatments that fall within the optimized area were predicted to result in a peanut with a trans-resveratrol > or = 1.0 microg/g; slightly lower roasted peanut aroma (> 24) and flavor (> 43); peanut butter aroma (> 14), and flavor (> 31) compared to controls with attribute ratings of 33, 78, 38, and 51, respectively; and slightly higher oxidized aroma (< 6), and painty (< 0.5), fishy (< 6), and cardboard flavor (> 4) compared to controls rated 0 for all attributes.

Mycotoxins in Australia: biocontrol of aflatoxin in peanuts.

The major mycotoxin problem in Australia is the formation of aflatoxins in peanuts by Aspergillus flavus and A. parasiticus. This is controlled by good farm management practice, segregation into grades on aflatoxin content at intake to shelling facilities, colour sorting and aflatoxin assays. A second problem is the potential presence of ochratoxin A in grapes and grape products, resulting from infection by Aspergillus carbonarius. Good quality control before and during wine making ensures ochratoxin A is kept to very low levels, but in dried vine fruit, ochratoxin A levels may be higher. Biocontrol by competitive exclusion has been developed as the most promising means of controlling aflatoxins in peanuts. Some details of the process are given, including some basic laboratory experiments.

Value assignment of nutrient and aflatoxin concentrations in standard reference material 2387 peanut butter.

Standard Reference Material (SRM) 2387 peanut butter was recently issued, and the process used for value assignment of nutrient and aflatoxin concentrations is reported herein. Values were assigned using data provided by the National Institute of Standards and Technology (NIST) and collaborating laboratories. SRM 2387 is intended for use as a primary material for assigning values to in-house control materials and for validation of analytical methods for measurements in peanut butter and similar high-fat matrixes. SRM 2387 lies in sector 3 of AOAC International's fat-protein-carbohydrate triangle. With the addition of SRM 2387, NIST now offers materials within-or on the borders between-all sectors of the triangle. The Certificate of Analysis for SRM 2387 provides assigned values for concentrations of fatty acids, proximates, elements, and total dietary fiber, for which product labeling is required by the Nutrition Labeling and Education Act of 1990, as well as several vitamins, amino acids, and aflatoxins, for which labeling is not required. (Aflatoxin levels in peanut butter are regulated by the Food and Drug Administration.)

Digestible threonine requirement of broiler chickens during the period three to six and six to eight weeks posthatching.

Four experiments were conducted to determine the digestible Thr requirement of commercial broiler chickens (Ross x Hubbard) during the period 3 to 6 and 6 to 8 wk posthatching. Threonine-deficient corn-peanut meal basal diets (3,200 MEn/kg) contained 20% CP and 0.50% Thr for 3- to 6-wk-old birds, and 18.3% CP and 0.50% Thr for 6- to 8-wk-old birds. True digestibility assessment using cecectomized roosters indicated that Thr was 81% digestible in both basal diets. Thus, both diets contained 0.40% digestible Thr. Growth rate and feed efficiency of chicks fed the corn-peanut meal basal diets supplemented with surfeit Thr was equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. Graded doses of Thr produced marked responses (P < 0.05) in weight gain and feed efficiency in birds of both age groups. Maximal feed efficiency was achieved at 0.61% digestible Thr in 3- to 6-wk-old birds and at 0.52% digestible Thr in 6- to 8-wk-old birds. Extrapolating these digestible Thr requirements to total requirements for chicks consuming corn-soybean meal diets (Thr digestibility = 87%) results in estimates of 0.70 and 0.60% for broiler chickens during the growth periods 3 to 6 and 6 to 8 wk posthatching, respectively. These estimates are lower than those of NRC (1994) but are in close agreement with those obtained from ideal protein calculations, i.e., Thr requirements should be 70% of lysine requirements for chicks 3 to 8 wk of age.

Effects of overprocessing on the nutritional quality of peanut meal.

Two experiments were conducted to evaluate the effects of overprocessing by autoclaving on the in vivo protein quality and in vitro protein solubility in 0.2% KOH of solvent-extracted peanut meal containing 48% protein. The peanut meal was autoclaved at 120 C and 105 kPa for 0, 20, 30, 40, 50, 60, or 90 min. In vivo protein quality of the autoclaved peanut meal was evaluated in chicks fed corn-peanut meal diets (22.5% protein) from 8 to 22 d of age and in adult cecectomized roosters using a precision-fed amino acid digestibility assay. Chick performance was significantly decreased when peanut meal had been autoclaved (P < 0.05) 60 min or more in one experiment and by 40 min or more in the other experiment. True digestibility of amino acids in peanut meal also decreased as autoclaving time increased. The effect of autoclaving was greatest for lysine, wherein digestibility was 87, 72, 68, and 57% for peanut meal autoclaved for 0, 30, 60, or 90 min, respectively. Protein solubility of peanut meal in 0.2% KOH decreased from 78 to 56% as autoclaving time increased from 0 to 90 min. Protein solubility values of 70% or lower were indicative of decreased in vivo peanut meal quality. The results of this study indicated that overprocessing by autoclaving reduces the protein quality of peanut meal and that protein solubility in KOH is a useful in vitro index of overprocessing.

Improving feeding management and work performance of Mashona oxen through strategic supplementation with cobsheath-groundnut stover.

Six pairs of Mashona oxen ploughed dry, red clay soils in August (winter) and in mid-November (spring). Between September and November the oxen were randomly assigned to 3 feeding groups: no supplement (control), 400 g/head per day of cobsheath-groundnut stover for 70 days and 800 g/head per day of the same supplement for 35 days. Cobsheath-groundnut stover was fed in order to determine its potential as supplementary feed for draught oxen during the dry season. The liveweight (LW) lost by heavy oxen during winter ploughing was lower (P < 0.001) than that of light oxen. During spring ploughing heavy oxen again lost less (P < 0.001) LW than light ones. In addition, non-supplemented oxen lost more LW than those supplemented. Therefore feeding strategies for Mashona draught oxen should aim at providing adequate nutrients to at least maintain LW during the dry season. Heavy oxen outperformed (P < 0.001) light ones during winter ploughing. Work output of supplemented oxen in spring was also significantly greater (P < 0.05) than that of non-supplemented ones. This result demonstrated the benefits of supplementary feed during the dry season. Concentrations of lactate and free fatty acids in plasma, heart rates and rectal temperatures increased (P < 0.05) markedly during work. The increases were higher (P < 0.05) for light oxen, particularly those not fed supplement.

Performance, carcass yield, and carcass quality characteristics of steers finished on rhizoma peanut (Arachis glabrata)-tropical grass pasture or concentrate.

Steers (n = 156) finished on rhizoma peanut (Arachis glabrata Benth.)-tropical grass pasture in Florida and slaughtered at Central Packing, Center Hill were compared with steers (n = 152) finished on a concentrate diet in Texas and slaughtered at Excel, Plainview. Average daily gain during the growing and finishing periods was lower (P < .001) for forage-finished steers (.49 and .94 kg/d, respectively) than for concentrate-finished steers (.78 and 1.33 kg/d, respectively). Forage-finished steers had less fat over the ribeye (8.3 vs 11.4 mm; P < .01), lighter hot carcass weight (280 vs 346 kg; P < .001), and smaller longissimus muscle area (70.8 vs 86.6 cm2; P < .001) than concentrate-finished steers. Yield grade was not different (2.7 vs 2.6; P > .10), but quality grade was slightly better (low Select vs mid Select; P < .01) for concentrate-finished steers. Lean color of forage-finished steers was darker (P < .001) and fat of forage-finished steers had a creamier color (P < .001), but carcasses were not discounted due to yellow fat color. Shear force values were higher (6.8 vs 4.0 kg; P < .001) for forage-finished than for concentrate-finished steers. Off-flavors were detected by trained sensory panelists in 36% of forage-finished and 14% of concentrate-finished carcasses, but all at barely detectable levels. This research indicates that steers can be finished on rhizoma peanut-tropical grass pastures, but with some reduction in quality grade relative to concentrate-finished steers.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance and nutrient digestibility in weanling pigs as influenced by yeast culture additions to starter diets containing dried whey or one of two fiber sources.

Three experiments were conducted using crossbred weanling pigs (7.2 to 8.6 kg; 25 to 29 d of age) to determine the effect on performance and nutrient digestibility of .75% yeast culture (YC) additions to starter diets containing whey or one of two fiber sources. An 18% CP corn-soybean meal basal diet was used in all experiments. In Exp. 1 (n = 192), the addition of YC did not affect ADG, ADFI, or gain: feed ratios (G:F) of pigs fed diets without or with 15% dried whey in two 5-wk trials. In Exp. 2 (n = 174), ADG and ADFI were not affected by YC addition to diets containing no added fiber, 8% soybean hulls (SH), or 8% peanut hulls (PH) in two 5-wk trials. The addition of SH or PH did not affect ADG or ADFI; however, a YC x SH interaction (P < .05) and a YC x PH interaction (P < .10) for G:F indicated that the addition of SH or PH to the diet in the absence of YC reduced G:F, but in the presence of YC, G:F were maintained. In a 3-wk grower phase of one trial in Exp. 2 (n = 54), SH and PH additions decreased ADG (P < .005), whereas YC additions improved ADG (P < .01), particularly for pigs fed diets that also contained SH (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

The preparation, validation and certification of the aflatoxin content of two peanut butter reference materials.

The preparation of two peanut butter reference materials and the certification of their aflatoxins B1, B2, G1, G2 and total aflatoxin contents is described. The materials were prepared and certified within the BCR Programme of the Commission of the European Community as part of a broad activity to improve accuracy and agreement of measurements of importance in food and agriculture (Wagstaffe and Belliardo 1990). Reference material RM 385 was prepared from naturally contaminated peanuts, roasted and ground into a paste and then blended with uncontaminated peanut butter to achieve the desired aflatoxin concentrations. Details are given of the blending and canning procedure, and the checks to ensure homogeneity and stability of the material. Reference material RM 401 was similarly prepared but from an uncontaminated peanut butter. The certification exercise was carried out by nine laboratories using a variety of extraction and clean-up procedures, but all using high performance liquid chromatography (HPLC) as the determinative stage although operating under a variety of chromatographic conditions. RM 385 was certified as containing aflatoxins B1, B2, G1 and G2 at levels of 7.0 +/- 0.8 micrograms/kg, 1.1 +/- 0.2 micrograms/kg, 1.7 +/- 0.3 micrograms/kg and 0.3 +/- 0.2 micrograms/kg respectively (total aflatoxin content of 10.1 +/- 1.5 micrograms/kg) and RM 401 as containing aflatoxin B1, B2 and G2 at less than 0.2 micrograms/kg and aflatoxin G1 at less than 0.3 micrograms/kg (total aflatoxin content less than 0.9 micrograms/kg). The materials are intended for the verification of methods used to determine aflatoxins in nuts and nut products.

Apparent and true availability of amino acids from common feed ingredients for channel catfish.

The apparent and true amino acid availability values for corn, wheat middlings, rice bran, rice mill feed, soybean meal, peanut meal, cottonseed meal, meat and bone meal, and two different samples of menhaden fish meal were determined in adult channel catfish. Although there was reasonable agreement between protein digestibility values and average amino acid availability values, individual amino acid availabilities were variable within and among the various feed ingredients tested. Therefore, we recommended that amino acid availability values should be used for more accurate catfish feed formulation. In addition, it appears that the use of true amino acid availability values should be used for feed ingredients of relatively low protein content.

Aflatoxin control: past and present.

Domestic commodities most susceptible to aflatoxin contamination are peanuts, corn, cottonseed, and tree nuts (almond, pecans, walnuts); the most susceptible imported commodities are Brazil nuts and pistachio nuts. The development, effectiveness, and shortcomings of the strategies used to limit consumer exposure to aflatoxin from these commodities are reviewed.

[Aflatoxin inactivation after ammonia treatment. In vitro studies on detoxified peanut meals]. / Inactivation des aflatoxines par traitement a l'ammoniac. Etudes in vitro de tourteaux d'arachide détoxiqués.

The maximum allowable tolerance of aflatoxins in animal feeds is becoming lower and lower, and it is obvious that the fairly high level of aflatoxin B1 found in almost all peanut meals in recent years restricts this protein source for use in the diets of most animal species. Among the different chemical methods for aflatoxin inactivation, treatment by gaseous ammonia under a pressure of 2 to 3 bars, appears a very attractive solution because it may be achieved by a fairly easy and rapid procedure. This treatment markedly reduces--up to 95 p. 100--the aflatoxins content of the meal. An increase in the nitrogen content, mainly in the non protein form, is observed. Ammoniation has no adverse effect on in vitro pepsin digestibility and even improves the sensitivity of the meal towards proteases. It slightly reduces protein deamination in the artificial rumen and nitrogen solubility in a buffer solution at pH 7,5; these effects seem to be favourable for the utilization of the treated meals by rumiinants. The amino acid compostion of the meal is not significantly changed, particularly with regard to total and available lysine. However, cystine undergoes partial destruction; but this loss could be counterbalanced by a supply of synthetic methionine.