In vitro digestion of spermidine and amino acids in fresh and processed Agaricus bisporus mushroom.

Mushrooms are significant sources of amino acids and bioactive amines; however, their bioaccessibility can be affected by processing and during in vitro digestion. Fresh Agaricus bisporus mushroom was submitted to cooking and canning and samples were submitted to in vitro gastric and gastric-intestinal digestions. An UHPLC method was used for the simultaneous determination of 18 free amino acids, 10 biogenic amines and ammonia in the samples. Fresh mushroom contained 14 free amino acids, with predominance of alanine and glutamic acid; spermidine was the only amine detected; and ammonia was also detected. Spermidine levels were not affected by cooking, but there was a significant loss (14%) after canning. Spermidine levels were not affected by the in vitro gastric and intestinal digestion, suggesting full bioaccessibility. There was a significant decrease on total amino acids levels after cooking and canning, with higher losses for aspartic and glutamic acids in cooked and for aspartic acid and valine in canned mushrooms. After the in vitro gastric and intestinal digestions, the total levels of amino acids increased and two additional amino acids (arginine and methionine) were detected. During in vitro digestion many of the amino acids were released mainly in the intestinal phase. After in vitro digestion, amino acids per gram of protein of mushrooms are adequate for most FAO amino acid pattern for adults. Multivariate analysis confirmed that protein hydrolysis in processed mushrooms is higher in intestinal phase. Bioaccessibility data for spermidine in A. bisporus is a novelty and increase the value of this food.

Total mercury in commercial fishes and estimation of Brazilian dietary exposure to methylmercury.

BACKGROUND: Mercury, in particular its most toxic form methylmercury, poses a risk to public health. Dietary methylmercury exposure is mainly by fish, and it can vary with fish contamination and by dietary habits of the population. This study aimed to quantify total mercury levels in different fish from Brazil and to estimate Brazilian exposure to methylmercury by fish consumption. METHODS: Total mercury occurrence was investigated in 18 different fish species by atomic absorption spectrometry with thermal decomposition and gold amalgamation. Dietary exposure to methylmercury was estimated by a deterministic method for different groups considering consumption by sex, different Brazilian geographical regions and habitat (rural or urban). RESULTS: Carnivorous fish showed higher levels of mercury (0.01 to 0.93 mg/kg) compared to non-strictly carnivorous fish (<0.01 to 0.30 mg/kg). Farmed fishes showed significantly lower levels compared to wild fish. Mean Brazilian fish consumption achieves FAO/WHO health recommendation of about two portions of fish per week. However, there is a large difference between fish consumption at urban and rural homes and among Brazilian geographic regions. These differences in consumption impacted estimated methylmercury intake that was higher in the Northern (1.85 µg/kg bw week) and in the Northeastern (0.72 µg/kg bw week) regions and also by rural population (1.08 µg/kg bw week). These values were compared with the toxicological reference dose for neurotoxicity of 1.6 µg/kg bw week. CONCLUSION: Even though total levels of mercury in fish were lower than Brazilian and international legislations, in the Northern Brazilian region methylmercury intake overpassed the toxicological reference dose for neurotoxicity and in rural areas it achieved 68% of this reference dose.

Synephrine - A potential biomarker for orange honey authenticity.

A LC-MS/MS method for synephrine as a biomarker for orange honey authenticity was developed and validated. The sample was extracted with 5% TCA and cleaned up with Florisil providing 83.7% recoveries. Ions transitions for quantification and identification were 168→135.0 and 168→107.0, respectively. The limits of detection and quantification were 0.66 and 1.0ng/g, respectively. Synephrine was detected in orange honey at levels from 79.2 to 432.2ng/g, but not in other monofloral honeys. It was also present in some wildflower honeys (9.4-236.5ng/g), showing contribution of citrus to this polyfloral honey. Results were confirmed by qualitative pollen analysis. No citrus pollen was detected in honey containing synephrine levels ≤43.8ng/g, suggesting that synephrine in honey is more sensitive compared to pollen analysis. Synephrine was found in citrus but not in other apiculture flowers. Therefore, synephrine is a botanical marker to differentiate and attest authenticity of orange honey.

Advances on the chromatographic determination of amphenicols in food.

Antibiotics are widely used in veterinary medicine to treat and prevent diseases and their residues can remain in food of animal origin causing adverse effects to human health. Amphenicols (chloramphenicol, thiamphenicol, and florfenicol) may be found in foodstuffs, although the use of chloramphenicol has been prohibited in many countries due to its high toxicity. Since these antibiotics are usually present at trace levels in food, sensitive and selective techniques are required to detect them. This paper reviews analytical methods used since 2002 for the quantitative analysis of amphenicols in food. Sample preparation and separation/detection techniques are described and compared. The advantages and disadvantages of these procedures are discussed. Furthermore, the worldwide legislation and occurrence of these antibiotics in food matrices as well as future trends are also presented.

Quality assurance of histamine analysis in fresh and canned fish.

Histamine determination is relevant for fish safety, quality and trade. Recently a study by the European Union (EU) compared the Codex and the EU mandated methods for the analysis of histamine and observed that they underestimated and overestimated the results, respectively. To solve this problem, a simple and efficient procedure for the extraction and quantification of histamine by ion-pair HPLC method with post-column derivatization and fluorimetric detection is proposed. It was optimized and validated for the analysis of histamine in fish. The method attended the performance criteria established by Commission Decision 2002/657/CE. The method was also submitted to proficiency testing; uncertainty was calculated; and the stability of solutions and standards was investigated. There was no matrix effect. The LOD, LOQ, CCα and CCß were fit for the purpose. The method was successfully used in the analyses of freshwater fish and fresh and canned tuna.