Functional Properties of Select Dry Bean Seeds and Flours.

Select functional properties of 21 dry beans and soybean seeds and their corresponding flours were evaluated. Among the tested seeds, dark-red and light-red kidney beans had larger length (L)/breadth (B) ratios than the rest. Lentil seeds were the smallest (L/B = 0.98), thinnest (2.23 mm), and lightest (density 1.14 g/cm3 ) among the tested seeds. Garbanzo seeds were the thickest (thickness 7.05 mm). Highest bulk density (g/cm3 ), porosity (%), specific volume (cm3 /g), and bulk volume (cm3 /g) were registered, respectively, by moth bean (0.86 g/cm3 ), pink bean (66.53%), lentil (0.88 cm3 /g), and soybean (1.46 cm3 /g) seeds. Water uptake during soaking peaked in ≤12 hr by all bean seeds. Soybean and black bean flours, respectively, exhibited the highest water-holding (3.14 g/g) and oil-holding (2.15 g/g) capacities. Great Northern bean flour exhibited higher foaming volume (30.8% increase) than all the other tested seed flours. Stability of all bean flour foams were ≤36 hr. Black gram flour formed a gel at the lowest concentration (4% w/v) among all the tested seed flours. Garbanzo, soybean, tepary, and val bean flours failed to form a gel at ≤ 20% (w/v). The results indicate that the tested dry bean flours have great potential as functional ingredients for food formulations. PRACTICAL APPLICATION: Understanding the functional properties of the dry bean seeds and flours is important for designing handling, transportation, storage, and processing methods for these beans and in guiding the selection of appropriate dry bean flours as food ingredients.

Comparison of Laboratory-Developed and Commercial Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assays for Almond (Prunus dulcis) Detection and Quantification.

A commercially available monoclonal antibody (mAb)-based direct sandwich enzyme-linked immunosorbent assay (ELISA) kit (BioFront Technologies, Tallahassee, Fla., U.S.A.) was compared with an in-house developed mAb 4C10-based ELISA for almond detection. The assays were comparable in sensitivity (limit of detection < 1 ppm full fat almond, limit of quantification < 5 ppm full fat almond), specificity (no cross-reactivity with 156 tested foods at a concentration of 100000 ppm whole sample), and reproducibility (intra- and interassay variability < 15% CV). The target antigens were stable and detectable in whole almond seeds subjected to autoclaving, blanching, frying, microwaving, and dry roasting. The almond recovery ranges for spiked food matrices were 84.3% to 124.6% for 4C10 ELISA and 81.2% to 127.4% for MonoTrace ELISA. The almond recovery ranges for commercial and laboratory prepared foods with declared/known almond amount were 30.9% to 161.2% for 4C10 ELISA and 38.1% to 207.6% for MonoTrace ELISA. Neither assay registered any false-positive or negative results among the tested commercial and laboratory prepared samples. PRACTICAL APPLICATION: Ability to detect and quantify trace amounts of almonds is important for improving safety of almond sensitive consumers. Two monoclonal antibody-based ELISAs were compared for almond detection. The information is useful to food industry, regulatory agencies, scientific community, and almond consumers.

Effects of the Maillard Reaction on the Immunoreactivity of Amandin in Food Matrices.

Amandin is the major storage protein and allergen in almond seeds. Foods, containing almonds, subjected to thermal processing typically experience Maillard browning reaction. The resulting destruction of amino groups, protein glycation, and/or denaturation may alter amandin immunoreactivity. Amandin immunoreactivity of variously processed almond containing foods was therefore the focus of the current investigation. Commercial and laboratory prepared foods, including those likely to have been subjected to Maillard browning, were objectively assessed by determining Hunter L* , a* , b* values. The L* values for the tested samples were in the range of 31.75 to 85.28 consistent with Maillard browning. Three murine monoclonal antibodies, 4C10, 4F10, and 2A3, were used to determine the immunoreactivity of the targeted samples using immunoassays (ELISA, Western blot, dot blot). The tested foods did not exhibit cross-reactivity indicating that the immunoassays were amandin specific. For sandwich ELISAs, ratio (R) of sample immunoreactivity to reference immunoreactivity was calculated. The ranges of R values were 0.67 to 15.19 (4C10), 1.00 to 11.83 (4F10), and 0.77 to 23.30 (2A3). The results of dot blot and Western blot were consistent with those of ELISAs. Results of these investigations demonstrate that amandin is a stable marker protein for almond detection regardless of the degree of amandin denaturation and/or destruction as a consequence of Maillard reaction encountered under the tested processing conditions. PRACTICAL APPLICATION: Foods containing almond are often subjected to processing prior to consumption. Amandin, the major allergen in almond, may experience Maillard reaction. Understanding the change in amandin immunoreactivity as a result of Maillard reaction is important for amandin detection and production of hypoallergenic food products.

Pistachio (Pistacia vera L.) Detection and Quantification Using a Murine Monoclonal Antibody-Based Direct Sandwich Enzyme-Linked Immunosorbent Assay.

A commercially available direct sandwich enzyme-linked immunosorbent assay (ELISA) (BioFront Technologies, Tallahassee, FL, USA) using murine anti-pistachio monoclonal antibodies (mAbs) as capture and detection antibodies was evaluated. The assay was sensitive (limit of detection = 0.09 ± 0.02 ppm full fat pistachio, linear detection range = 0.5-36 ppm, 50% maximum signal concentration = 7.9 ± 0.7 ppm), reproducible (intra- and inter-assay variability < 24% CV), and rapid (post-extraction testing time ∼ 1.5 h). The target antigen was stable and detectable in whole pistachio seeds subjected to autoclaving (121 °C, 15 psi, 15, 30 min), blanching (100 °C, 5, 10 min), frying (191 °C, 1 min), microwaving (500, 1000 W, 3 min), and dry roasting (140 °C, 30 min; 168 °C, 12 min). No cross-reactivity was observed in 156 food matrices, each tested at 100,000 ppm, suggesting the ELISA to be pistachio specific. The pistachio recovery ranges for spiked (10 ppm) and incurred (10-50000 ppm) food matrices were 93.1-125.6% and 35.7-112.2%, respectively. The assay did not register any false-positive or -negative results among the tested commercial and laboratory prepared samples.