Association Of Official Analytical Chemists Method Research Articles

Perbandingan Kadar Air, Asam Lemak Bebas dan Bilangan Peroksida Pada Minyak Curah dan Minyak Tandusan di Desa Baluk, Jembrana

The scarcity of cooking oil in various regions is a major problem in the food security sector. One alternative that can be done to overcome this phenomenon is to develop tandusan oil as a product of local wisdom in Baluk Village, Jembrana. The purpose of this study was to determine the water content, free fatty acids, and peroxide number of the tandusan oil and compare it with the bulk oil on the market. Testing the oil quality parameters each uses three samples with the AOAC (Association of Official Analytical Chemists) method. The test results from this study obtained that the water content in the three samples of tandusan oil was 0.16%; 0.12%; and 0.14% while in the bulk oil sample it was 0.47%; 0.45%; and 0.48%. The free fatty acid content obtained from the tandusan oil test was 0.49%; 0.42%; and 0.46% while in the bulk oil sample it was 2.39%; 2.41%; and 2.45%. The measured peroxide number in the tandusan oil was 0.52 mg eq/kg; 0.55 mg eq/kg; and 0.50 mg eq/kg whereas in the bulk oil it is 3.49 mg eq/kg; 3.55 mg eq/kg; and 3.59 mg eq/kg. Tandusan oil has better oil quality than bulk oil and meets SNI 2902:2011 and SNI 3741: 2013 so it is safe to use as food.

The Effect of Monsoon on Chemical Composition and Bioaccumulation of Heavy Metals in Scomberomorus commerson, Lacepede 1800, from Oman Sea

This study was performed to determine the chemical compositions and heavy metals in the muscle of Scomberomorus commerson from the Oman Sea, during the two seasons, pre-monsoon and post-monsoon in 2018. The protein, fat, moisture, and ash contents were determined by AOAC (Association of Official Analytical Chemists) methods. Heavy metal (Zn, Cu, and Pb) analyses were performed by atomic absorption spectrophotometer after acid digestion. There were significant differences between protein, fat, moisture, and ash values in muscle tissue in two seasons (P Cu>Pb. The amounts of Zn, Cu, and Pb were below maximum permissible limits (MPL) recommended by international standards (FAO, FAO/WHO, and MAFF). Results revealed that estimated daily and weekly intakes of Zn, Cu, and Pb were far below the permissible tolerable daily intake (PTWI) recommended by FAO/WHO. Therefore, consumption of S. commerson in the pre and post-monsoon has no risks for human health in the Oman Sea.

Biochemical Composition of Two Zinziberaceae: Ginger (Zingiber officinale roscoe) and Turmeric (Curcuma longa)

The objective of this work is to analyze the biochemical parameters of Zingiber officinale (ginger) and Curcuma Longa (turmeric) found in the locality of Daloa. The samples were purchased in the markets of Daloa. The dry matter, ash and lipid contents were determined by the AOAC (Association of Official Analytical Chemists) method. Those of proteins, total sugars, reducing sugars were carried out respectively by the methods of Kjeldahl, Bernfeld and Dubois. A phytochemical study was done by Evans method. The contents of total flavonoids and total polyphenols were determined respectively according to the methods of Wood and Marinova. It emerges from the analyzes that the contents of dry matter (27.66 ± 0.06%), total sugars (31.25 ± 0.6 mg / g) and fibers (8.21 ± 0.01%) are higher in ginger than in turmeric. The lipid contents of the two species are less than 8%. The results also reveal the presence of tannins, saponins, polyphenols, alkaloids and flavonoids. Ginger has a high content of total polyphenols (53.55 ± 0.45 mg EAG / g) than turmeric (35.25 ± 0.52 mg EAG / g). However, the flavonoid values ​​are high in turmeric (92.52 ± 0.54 µg EQ / g) than ginger (86.27 ± 0.62 µg EQ / g). Both turmeric have revealed that ginger and turmeric are low in fat, reducing sugars, and high in fiber and polyphenols. Both rhizomes have the same protein content. The presence of secondary metabolites in the rhizomes of ginger and turmeric justifies the therapeutic importance of these two plants, hence the importance of consuming them to take full advantage of the beneficial effects of its active ingredients. However, the compounds vary from species to species.

Comparative Assessment of the Basic Chemical Composition and Antioxidant Activity of Stevia rebaudiana Bertoni Dried Leaves, Grown in Poland, Paraguay and Brazil—Preliminary Results

This study compares the content of basic nutrients (proteins, fats, digestible carbohydrates, dietary fiber and ash), steviol glycosides, selected antioxidants (vitamin C, total polyphenols) and antioxidant activity in dried leaves of Stevia rebaudiana Bertoni cultivated in Poland, Paraguay and Brazil and available in the direct sale. The basic chemical composition was determined by standard AOAC (Association of Official Analytical Chemists) methods. Content of steviol glycosides was determined by the UHPLC-UV chromatographic method. Total polyphenols content was expressed as gallic acid equivalent (GAE) and catechins equivalent (CE). Antioxidant activity was measured as ABTS●+ free radical scavenging activity. Dried leaves of S. rebaudiana grown in Poland had significantly higher contents of dietary fiber, and lower protein and ash content, compared to those derived from Paraguay and Brazil. The former had, however, considerably higher contents of total steviol glycosides, stevioside and rebaudioside D, compared to the remaining two plants. In the Paraguay-derived dried leaves, the content of rebaudioside A, C, E and rubusoside was found to be significantly lower. Dried leaves of S. rebaudiana Bertoni, cultivated in Poland, contained substantially more vitamin C and a similar content of total polyphenols, compared to those from Brazil and Paraguay. The examined material from Brazil and Paraguay plantations showed similar antioxidant activity, while that obtained from Polish cultivation was characterized by a significantly lower value of this parameter.

Valorization of Banana and Red Beetroot Peels: Determination of Basic Macrocomponent Composition, Application of Novel Extraction Methodology and Assessment of Biological Activity In Vitro

The nutritional and bioactive content of banana and red beetroot peels was investigated. The basic macrocomponent composition was determined using standard AOAC (Association of Official Analytical Chemists) methods, while the recovery efficiency of bioactive compounds was investigated using conventional and innovative extraction techniques (subcritical water extraction, ultrasound- and microwave-assisted extraction). Extracts were analyzed for biological effects in vitro on human hepatic, tongue and colon cancer cell lines. A macrocomponent analysis revealed a notable amount of dietary fiber in banana and beetroot peels (39.0 and 33.6% dmb) and a relatively high content of protein in beetroot peel (18.3% dmb). Regarding the micronutrients-minerals, banana and beetroot peels were shown to be a very good source of potassium (75.06 and 41.86 mg g−1 dmb). Both extracts of banana and beetroot peels obtained by conventional extraction - decoction (100 °C, 20 min) exhibited the highest total phenolic content and antioxidant capacity. Additionally, in banana peel, these extracts were the richest in dopamine content (12.63 mg g−1 dmb). Extraction by infusion (80 °C, 30 min) yielded a beetroot peel extract with the highest total betacyanin content (9.80 mg g−1 dmb). Biological effects in vitro were dose- and time-dependent, as well as influenced by the presence of polysaccharides.

An environment-friendly spot test method with digital imaging for the micro-titration of citric fruits

A new method to determine the total titratable acidity of orange, lemon and passion fruit, based on a spot test obtained from digital images and using anthocyanins as the biodegradable indicator, is presented for the first time. The colorimetric reactions were carried out by acid-base titration on a microscale, employing anthocyanin with a microplate for spot test purposes, with detection by digital imaging. To obtain highly precise data, a chamber based on a diffuser was developed to control the illumination supplied by the light emitting diodes, and coupled to a smartphone to acquire adequate digital images. High precision was obtained with a relative standard deviation of 0.758% for n = 95. The RGB values were extracted from the digital images and used as analytical signals, the values being correlated with the micro-volume of the titrant and used to construct the titration curves and obtain the first and second derivatives, respectively. For comparative purposes, the official AOAC (Association of Official Analytical Chemists) and MAPA (Ministry of Agriculture, Livestock and Food Supply of Brazil) methods were used and the results compared by applying the paired t-test at the 95% confidence level (n = 3). No difference was found between the values and the relative errors were less than 2.8%. The micro-titrimetric method was fast, uses anthocyanins as the natural indicator, is practical, and permits a reduction of 922 times or 99.9% of the volume required in a conventional titration. It is therefore ideal for routine analyses leading to a reduction in the waste generated, according to the principles of green chemistry.

Structure, physicochemical properties and adsorption function of insoluble dietary fiber from ginseng residue: A potential functional ingredient

The insoluble dietary fiber from ginseng residue (ginseng-IDF) was extracted using the AOAC (Association of Official Analytical Chemists) method with content of 68.61%. Ginseng-IDF had a polysaccharide content of 18.87%, uronic acid content of 7.85%, protein content of 6.52%, and had ideal water-holding capacity (17.66 g/g), swelling ability (15.05 mL/g), and oil-holding capacity (1.78 g/g). Scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction analyses suggested that ginseng-IDF had the typical structures of hydrolysis fiber, polysaccharide functional groups, and crystal structure of cellulose. Different fiber components give ginseng-IDF a specified range of pyrolysis temperature, and it is suitable for application in food processing lower than 300 °C. In addition, ginseng-IDF exhibited notable glucose and sodium cholate adsorption, significantly improved nitrite adsorption at pH 2.0 and cholesterol adsorption at pH 7.0. The above results show that ginseng-IDF could be used as an ideal functional ingredient in food processing.

Development and evaluation of nutritional, sensory and glycemic properties of finger millet (Eleusine coracana L.) based food products.

Finger millet (Eleusine coracana L.) (FM) is rich in dietary fibre and is therefore expected to elicit a lower glycemic response compared to other grains. However, there is little data on the glycemic properties of FM-based products. We evaluated the nutritional, sensory and glycemic properties of decorticated millet with lower polish (DFM-LDP), flakes (FMF), vermicelli (FMV) and extruded snack (FMES) (both FMV and FMES with 7-8% added soluble fibre). The nutrient contents of the FM products were evaluated by standard AOAC (Association of Official Analytical Chemists) and AACC (American Association of Cereal Chemists) methods. Sensory evaluation was conducted monadically using a 9-point hedonic scale using untrained panel members. GI testing was conducted using a standardized validated protocol. The study was conducted according to the guidelines laid down by the Declaration of Helsinki, and was approved by the Ethics Committee of the Madras Diabetes Research Foundation. The products had dietary fibre (DF) content between 5.8-15.6 g%. FMES was unique in having a very low fat content (0.17%). Evaluation of sensory perception revealed moderate acceptance of millet based products. The glycemic indices (GI) (mean±SEM) of the products were 84.7±7.7%, 82.3±6.4%, 65.5±5.1% and 65.0±6.6% for DFM-LDP, FMF, FMV and FMES respectively. DFM-LDP and FMF (purely finger millet based products) elicited higher glycemic responses. Comparatively, FMV and FMES (with added functional ingredients) exhibited medium GI values and, are healthier dietary options. It is possible to prepare FM products with lower GI by utilizing functional ingredients.

Prediction of peroxide value in omega-3 rich microalgae oil by ATR-FTIR spectroscopy combined with chemometrics.

Our work explored, for the first time, monitoring peroxide value (PV) of omega-3 rich algae oil using ATR-FTIR spectroscopic technique. The PV of the developed method was compared by that obtained by standard method of Association of Official Analytical Chemists (AOAC). In this study, peak area integration (PAI), Partial Least Squares Regression (PLSR), and Principal Component Regression (PCR) were used as the calibration techniques. PV obtained by the AOAC method and by FTIR-ATR technique were well correlated considering the peak area related to trans double bonds and chemometrics techniques of PLSR and PCR. Calibration model was established using the band with a peak point at 966cm-1 (990-940cm-1) related to CH out of plane deformation vibration of trans double bond. Algae oil oxidation could be successfully quantified using PAI, PLSR and PCR techniques. Additionally, hierarchical cluster analysis was performed and significant discrimination was observed coherently with oxidation process.

Optimization of Sample Preparation for the Identification and Quantification of Saxitoxin in Proficiency Test Mussel Sample using Liquid Chromatography-Tandem Mass Spectrometry.

Saxitoxin (STX) and some selected paralytic shellfish poisoning (PSP) analogues in mussel samples were identified and quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction and purification methods of mussel sample were optimized for LC-MS/MS analysis. The developed method was applied to the analysis of the homogenized mussel samples in the proficiency test (PT) within the EQuATox project (Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk). Ten laboratories from eight countries participated in the STX PT. Identification of PSP toxins in naturally contaminated mussel samples was performed by comparison of product ion spectra and retention times with those of reference standards. The quantitative results were obtained with LC-MS/MS by spiking reference standards in toxic mussel extracts. The results were within the z-score of ±1 when compared to the results measured with the official AOAC (Association of Official Analytical Chemists) method 2005.06, pre-column oxidation high-performance liquid chromatography with fluorescence detection (HPLC-FLD).

Grasshoppers Sphenarium Purpurascens Ch Source of Proteins and Essential Amino Acids

Protein malnutrition is quite common worldwide; its deficiency has adverse effects in all organs. Edible insect's traditional cultural food, commonly consumed in rural communities, now intake is also being incorporated in some countries. Grasshoppers comprise proteins, the building blocks of AA (amino acids), that are one of the five classes of complex biomolecules found in cells and tissues that play an important role in human metabolism and nutrition. This research was conducted to determine proximal composition of Sphenarium purpurascens Ch, grasshoppers, focused on proteins and AA. Sampling was performed during autumn, 2013, in Oaxaca State. Dry raw adult insects were ground and proceeded to macro molecules proximal analysis, protein by Kjeldahl AOAC (Association of Official Analytical Chemists) method and essential AA in a Beckman 6300 equipment. Obtained data were: total proteins 71.56%; lipids 8.14%; minerals 3.52%; fiber 7.48%; soluble carbohydrates 9.30%. Essential AA (mg/16 g·N): isoleucine 4.5; leucine 8.1; lysine 5.4; methionine + cysteine 5.1; phenylalanine + tyrosine 8.5; threonine 3.5; tryptophan 0.6; valine 5.5. Sphenarium purpurascens Ch, Grasshoppers represent a good source of proteins and essential AA that can grow almost everywhere, available mostly all year round and affordable to all social groups, thus being a good option to improve human health.

Determination of proline in honey: Comparison between official methods, optimization and validation of the analytical methodology

The study compares official spectrophotometric methods for the determination of proline content in honey – those of the International Honey Commission (IHC) and the Association of Official Analytical Chemists (AOAC) – with the original Ough method. Results show that the extra time-consuming treatment stages added by the IHC method with respect to the Ough method are pointless. We demonstrate that the AOACs method proves to be the best in terms of accuracy and time saving. The optimized waiting time for the absorbance recording is set at 35min from the removal of reaction tubes from the boiling bath used in the sample treatment. The optimized method was validated in the matrix: linearity up to 1800mgL−1, limit of detection 20mgL−1, limit of quantification 61mgL−1. The method was applied to 43 unifloral honey samples from the Marche region, Italy.

Comparative analysis of standardised and common modifications of methods for lipid extraction for the determination of fatty acids

► Lower solvent volumes can be used to quantify fatty acids with AOAC method. ► Mono- and poly-unsaturated fatty acids were underestimated with ISO method. ► Lipid peroxidation was lowest with ISO method, which uses high temperatures. Various standard techniques are commonly used for lipid extraction, but a comparative analysis amongst the different methods has not been assessed. To compare three commonly used procedures for the extraction of fatty acids from flaxseed, with adjustments for lower solvent volumes. Lipids were extracted from ground flaxseed using the International Organization for Standardization (ISO) method, the Association of Official Analytical Chemists (AOAC) method, the Folch method, and a modified AOAC procedure using lower solvent volume. Fatty acid concentrations and percent composition were determined by gas chromatography (GC) and the identities of the fatty acids were confirmed by gas chromatography–mass spectrometry (GC–MS). The extent of lipid peroxidation was also assessed using the thiobarbituric acid reactive species (TBARS) assay. GC analysis revealed that total fatty acid recoveries were not statistically different across the various methods ( P > 0.05). However, the ISO extraction procedure resulted in higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids, as compared with the Folch and conventional AOAC methods. Fatty acid concentrations were similar with the conventional high-volume and the modified low-solvent AOAC procedures. GCMS analysis confirmed the identity of the measured fatty acids. All assays produced TBARS, which were highest in the conventional AOAC method, followed by the Folch method ( P < 0.05) and the ISO method, respectively ( P < 0.05). Total fatty acid concentrations were equal after the different extraction methods. It appears that mono- and poly-unsaturated fatty acids in flaxseed are underestimated after extraction with the ISO method and that the solvent volumes used in the AOAC method can be decreased without compromising fatty acid concentrations. The lower yield in unsaturated fatty acids with the ISO method is not likely due to an increase in fatty acid peroxidation.

Sensitive Flow-Injection Amperometric Detection of Iodide Using Mn3+ and As3+

A rapid, selective, and sensitive kinetic flow-injection method for iodide content determination with amperometric detection on a platinum electrode was developed. The method is based on the catalytic effect of iodide on the Mn3+ reaction with As3+ in the presence of sulfuric acid. The calibration curve was linear in the concentration range from 5.0 x 10(-7) to 1.0 x 10(-4) mol/L iodide. The limit of detection (LOD) was found to be 5.0 x 10(-9) mol/L iodide. The relative standard deviations (RSD) were 1.68% and 3.03% for 1.0 x 10(-3) mol/L standard and 1.0 x 10(-6) mol/L iodide solution (n = 6), respectively. The method has been successfully applied for determination of iodide in waters, table salts, fodder, organic substances and human blood sera. The results were compared with those obtained by a standard AOAC (Association of Official Analytical Chemists) method, as well as with those obtained by a kinetic spectrophotometric procedure for determination of iodide.

Determination of Multipesticide Residues in Mentha piperita.

A general multiresidue method cannot be applied unconditionally to all medicinal plants to extract the residues of interest. The main objective here was to evaluate the Association of Official Analytical Chemists (AOAC) official method 985.22 with Mentha piperita. L. samples. This AOAC method is one of the methods used in pesticide residue labs worldwide. The proposed method proved to show adequate recovery, repeatability, and reproducibility for most of the studied pesticides, and no cleanup step was needed. More than one pesticide residue was contaminating the tested M. piperita. samples, and the number of pesticides found reflects the diversity of compounds used.

Initial interlaboratory validation of an analytical method for the determination of lead in canned tuna to be used for monitoring and regulatory purposes

The Association of Official Analytical Chemists (AOAC) Standard Method 972.23 (dry ashing and flame atomic absorption spectrophotometry (FAAS)), applied to the analysis of lead in tuna, was validated in three selected local laboratories to determine the acceptability of the method to both the Codex Alimentarius Commission (Codex) and the European Union (EU) Commission for monitoring lead in canned tuna. Initial validation showed that the standard AOAC method as performed in the three participating laboratories cannot satisfy the Codex/EU proposed criteria for the method detection limit for monitoring lead in fish at the present regulation level of 0.5 mg kg−1. Modification of the standard method by chelation/concentration of the digest solution before FAAS analysis showed that the modified method has the potential to meet Codex/EU criteria on sensitivity, accuracy and precision at the specified regulation level.

Impact of the proposed definition of dietary fiber on nutrient databases

Many definitions of dietary fiber exist worldwide, some based on analytical methods and others physiologically based. In March 2001, the Food and Nutrition Board, Institute of Medicine of the National Academy of Sciences released proposed definitions for dietary fiber developed by a panel of experts. The panel held three meetings and a workshop to review existing definitions of dietary fiber, review methods to measure dietary fiber, and receive input from scientists, food companies, consumers, and other interested parties on their viewpoints on a definition for dietary fiber. Based on the Panel's deliberations, the following definitions were proposed: Dietary Fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants. Functional Fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans. Total Fiber is the sum of Dietary Fiber and Functional Fiber. What impact will these definitions have, if adopted? Currently, dietary fiber is defined as compounds that are isolated by analytical dietary fiber methods accepted by the Association of Official Analytical Chemists (AOAC) rather than a formal definition that includes fiber's role in human health. New methods will need to be developed to reflect the accepted definitions for dietary fiber. Additionally, the committee felt that the terms “soluble” and “insoluble” fiber are not meaningful and should no longer be used in labeling. Finally, compounds such as resistant starch and inulin, which do not qualify as dietary fiber under current AOAC methods could be considered Functional Fiber if they show beneficial physiological effects in humans.

Investigation of dietary fibre in some edible mushrooms from Macedonia

Analyzes seven kinds of edible wild Macedonian mushrooms for their total dietary fibre (TDF) content, according to the official Association of Official Analytical Chemists (AOAC) method for plants as well as according to Hackman’s method for material of animal origin. Elemental analysis (C, H, N) of TDF procedures was performed in order to confirm the uniformity of the isolated products. The TDF contents of the mushrooms as measured by the AOAC method (8.71 per cent dry wt.) were considerably greater than those determined using the Hackman method (5.53 per cent dry wt.). Two products were isolated, both with C and H contents very similar to chitin and cellulose. These products differ from cellulose as they contain N. The infra‐red (IR) spectra of the TDF isolates obtained according to both the applied methods were very similar to the IR spectrum of chitin. In all spectra cellulose is missing.

Comparative Study of Recovery of Salmonella javiana from Mozzarella Cheese by Two Official Analytical Procedures

The Association of Official Analytical Chemists (AOAC) and the Canadian Health Protection Branch (CHPB) methods for detection of Salmonella spp. were compared for recovery of Salmonella javiana from experimentally contaminated mozzarella cheese. Ten trials were conducted with two levels of random surface contamination of cheese. Five samples per level of contamination were randomly chosen and analyzed by each method. The results showed that there was no significant difference between the two methods (P < 0.05). When S. javiana was directly added to shredded cheese and analyzed immediately, the recovery was identical with both methods; 7 of 10 samples were positive by each method. However, when the directly contaminated cheese was stored for 7 days and analyzed by both methods, the results differed. The AOAC method showed only 3 positive samples, whereas the CHPB yielded 6, compared to 7 positive samples before storage by both methods. During preenrichment the pH decreased to a greater extent with the AOAC method (7.4 to 4.4) than with the CHPB method (7.6 to 5.7) in 24 h; this pH decrease resulted in 1 log higher number of S. javiana counts in the latter (106 CFU/ml and 107 ml).

Dietary Fibre Content and Composition of Some Edible Fungi Determined by Two Methods of Analysis

Six common edible fungi from four orders of Basidiomycetes, namely Agaricus bisporus (Agaricales), Auricularia auricula and Auricularia polytricha (Auriculariales), Tremella fuciformis (Tremellates), Ganoderma lucidum and Poria cocos (Aphyllophorales), were analysed for their total dietary fibre (TDF) content using the Association of Official Analytical Chemists (AOAC) method and for dietary fibre content and composition using the Uppsala method. The non-protein nitrogen contributed from fungal chitin was corrected in the fibre residue obtained by the AOAC method. The TDF content measured by the AOAC method was always greater than that of the Uppsala method. The TDF content determined by the AOAC and Uppsala methods ranged from 182 and 132 g kg-1 (dry matter) in A bisporus to 735 and 711 g kg-1 (dry matter) in P cocos, respectively. Neutral and amino sugars were the dominant sugars in all the fungi. Sugar composition of the TDF reflected that the major cell wall polysaccharides in most fungi were hemicelluloses, such as β-glucan and glucuronoxylomannan, pectic substances and chitin. Judging from their high fibre content and unique fibre composition, edible fungi have considerable value as sources of dietary fibre in human nutrition. © 1997 SCI.