Sequential extractions: A new way for protein quantification—data from peanut allergens

Lentinula edodes mushroom as an ingredient to enhance the nutritional and functional properties of cereal bars

Lentinula edodes (shiitake) is the second most cultivated edible mushroom in the world; it has low lipid contents, high protein and it is source of vitamins and minerals. This study aimed to develop and to evaluate two sweet and two salty food bars containing shiitake. The binder elements were heated and then the dried elements were added. The bars were shaped, and the sensorial test was accomplished with hedonic scale of 9 points for analysis of texture, aroma, taste and appearance, and a 5-point scale for buying intention. The centesimal composition included percentages of moisture content, ashes, lipids, proteins and carbohydrate contents. Chemical elements of shiitake were quantified by Energy Dispersive X-ray Fluorescence. Glucans were determined using a commercial kit. Phenolic compounds were determined with the Folin-Ciocalteu reagent. The shelf life was evaluated by microbiological control, up to 180 days, at temperatures of 25 °C and 37 °C. The sweet bar 1 (SwB1) had better sensory analysis and buying intention. Shiitake showed high concentrations of calcium, iron, phosphorus, potassium, zinc, manganese, phenolic compounds and glucans. SwB1-bar maintained shiitake nutritional characteristics. SwB1-bars did not present microorganisms for up to 180 days of shelf life, neither at 25 °C nor at 37 °C, and they followed the standards determined by National Health Surveillance Agency. Sweet bars are an easy marketing alternative due to their stability, low-cost of production and good acceptance, as well as flexibility to add other functional ingredients beneficial to health, such as shiitake.

Shellfish Tropomyosin IgE Cross-Reactivity Differs Among Edible Insect Species

SCOPE

Insects are a potentially environmentally friendly alternative dietary protein source to supplement mammalian and fish sources, but potential allergenic risks are a concern. Consumption of insects may result in anaphylaxis and has been implicated in cross-reactivity with shellfish. Many allergenic proteins may be involved in cross-reactivity, including tropomyosin (TM). The uniformity of TM cross-reactivity among edible insects is unknown. Candidate edible insects for variability in shellfish IgE cross-reactivity are investigated.

METHODS AND RESULTS

Selected insects and known related sources of allergens are extracted and probed by immunoblot with sera/plasma from patients sensitized to insects or shellfish. Quantification of TM in these extracts is performed using mass spectrometry. A comparison of the quantity of TM and the IgE reactivity of TM from these insects is performed. Distinct patterns of IgE cross-reactivity are observed with three insect species showing diminished reactivity. This pattern is not consistent with the amount of TM present in these insects, or with overall sequence homology.

CONCLUSION

Insects display a diversity of TM-associated IgE reactivity. It is likely that minor sequence features and/or structural effects are primarily responsible. Additionally, it is demonstrated that some insect species may present significantly less IgE cross-reactivity to shrimp than do others.

Peanut protein extraction conditions strongly influence yield of allergens Ara h 1 and 2 and sensitivity of immunoassays

The clinical importance of peanut (Arachis hypogaea) allergies demands standardized allergen extraction protocols. We determined the effectiveness of common extraction conditions (20 buffers, defatting reagents, extraction time/temperatures, processing, extraction repeats) on crude protein and Ara h 1 and 2 yields. Despite similar 1D-gel profiles, defatting with n-hexane resulted in significantly higher yields of crude protein, Ara h 1, and Ara h 2 than with diethyl ether. The yields were affected by the composition and pH of the extraction buffers and other conditions, but crude protein yield did not always correlate with Ara h 1 and 2 yields. Denaturants, reducing agents, acidic buffers, and thermal processing of peanuts perturbed allergen quantification in ELISAs, probably via exposure of additional epitopes. Allergen detection in 2D-Western blots with PBS resulted in greater sensitivity than with TBS or Tris. We recommend that allergen extraction conditions be selected based on the research question being investigated.

Effects of Lentinula edodes consumption on biochemical, hematologic and oxidative stress parameters in rats receiving high-fat diet

PURPOSE

Functional foods can prevent/reduce the risks related to obesity. Lentinula edodes is a highly nutritious mushroom rich in protein, vitamins and minerals. Some studies have demonstrated the hypocholesterolemic effects from L. edodes in high doses, which does not represent the consumption in humans. We evaluated ingestion of a realistic dose of L. edodes associated with a high-fat diet (HFD) on hematologic, biochemical and oxidative stress parameters.

METHODS

Eighteen male Wistar rats were divided into three groups: control (normal diet); HFD; and HFD + L. edodes (100 mg/kg/day). After 30 days, blood was collected. Biochemical and hematologic parameters were analyzed, as well as oxidative stress biomarkers.

RESULTS

The HFD increased levels of total cholesterol and triglycerides. Lentinula edodes reduced these parameters significantly to concentrations found in the control group. The HFD increased levels of alanine transaminase and aspartate transaminase (markers of liver damage). Lentinula edodes returned the levels of these enzymes to normal levels and normalized serum levels of urea (which were also increased owing to consumption of the HFD). Lentinula edodes reduced levels of urea and glucose. Lipid peroxidation was increased in rats receiving the HFD, and L. edodes reduced malondialdehyde levels, thereby preventing oxidation of fatty acids.

CONCLUSIONS

Lentinula edodes was shown to have hypolipidemic, hypoglycemic, hepatoprotective and renoprotective features in doses that are suitable for humans.