Degree Of Thermal Processing Research Articles

The Effects of Diet Formulation and Thermal Processes Associated With Pelleting on 18-day Broiler Performance and Digestible Amino Acid Concentration

SUMMARY The objectives of the study were to assess performance and digestible amino acid concentration of diets fed to broilers that differed in formulation and degree of thermal processing. Basal diets were corn, soybean meal (SBM), and dried distillers grains and solubles (DDGS) based and formulations were balanced to be similar in calculated metabolizable energy and digestible amino acids. Treatments were arranged in a 3 × 3 factorial that varied in diet formulation (basal, basal + meat and bone meal (MBM), and basal + bakery byproduct (BBP)) and degree of thermal processing (unprocessed mash, pellet, double pellet). All treatments were ground to similar particle size and fed to 10 replicate raised wire cages of 10 straight-run Hubbard x Cobb 500 broiler chicks for 18 d. Broilers provided a basal + MBM diet improved FCR (P = 0.0046). Pelleting and double pelleting improved FCR compared to unprocessed mash (P = 0.0003). Formulation and processing effects interacted to affect digestible lysine, methionine, threonine, and cysteine concentrations (P

Mass spectrometric analysis of allergens in roasted walnuts

Thermal processing of allergenic foods can induce changes in the foods' constituent allergens, but the effects of heat treatment are poorly defined. Like other commonly allergenic tree nuts, walnuts often undergo heat treatment (e.g. roasting or baking) prior to consumption. This study evaluated the changes in solubility and detectability of allergens from roasted walnuts using tandem mass spectrometry methods. Walnuts were roasted (132°C or 180°C for 5, 10, or 20min) and prepared for LC-MS/MS using sequential or simultaneous extraction and tryptic digestion protocols. The LC-MS/MS data analysis incorporated label-free quantification of relevant allergens and Maillard adduct screening. In some proteins (2S albumin, LTP, and the 7S globulin N-terminal region) minor changes in relative abundance were observed following roasting. The mature 7S and 11S globulins, however, showed significantly increased detection following roasting at 180°C for 20min when using the simultaneous extraction/digestion protocol, possibly due to increased digestibility of the proteins. The results of this study indicate that individual walnut allergens respond differently to thermal processing, and the detection of these proteins by LC-MS/MS is dependent on the protein in question, its susceptibility to proteolytic digestion, the degree of thermal processing, and the sample preparation methodology. SignificanceUnderstanding the behavior of food allergens in the context of relevant food matrices is critical for both food allergen management and for elucidating matrix and processing-associated factors influencing protein allergenicity. The use of mass spectrometry to identify food allergens and detect allergenic food residues has been increasingly developed due to the advantages associated with the direct, sequence-level analysis possible with MS. To date, however, few studies have implemented MS technology to analyze the effects of thermal processing on allergenic food proteins. The MS analysis results presented in this study revealed not only information about the molecular-level effects of roasting on walnut allergens but also data pertinent to the development of MS-based detection methods for walnut residues in food products.

Hardness, ductility, and thermal processing of Cu/Zr and Cu/CuZr nanoscale multilayer foils

The hardness, ductility, and thermal processing of Cu/Zr and Cu/CuZr multilayers were investigated by indenting, bending, and heating a series of free-standing multilayer foils. The foils were deposited with alternate, nanoscale layers of Cu and Zr, and then thermally processed to produce three additional nanostructures: alternate layers of Cu and amorphous CuZr(aCuZr); alternate layers of Cu and Cu 51Zr 14; and a non-layered structure with small Cu grains in large Cu 9Zr 2 grains. The hardness and ductility of the foils depended strongly on the degree of thermal processing and varied dramatically with the volume fraction of the Zr or CuZr phases in each of the four nanostructures. The dependence of hardness on volume fraction was stronger when the films were indented parallel to their layering than when the foils were indented perpendicular to their layering. This result demonstrates that plastic deformation is anisotropic in these multilayer samples.

Noble gases in presolar diamonds I: Three distinct components and their implications for diamond origins

Abstract— High‐purity separates of presolar diamond were prepared from 14 primitive chondrites from 7 compositional groups. Their noble gases were measured using stepped pyrolysis. Three distinct noble gas components are present in diamonds, HL, P3, and P6, each of which is found to consist of five noble gases. P3, released between 200 °C and 900 °C, has a “planetary” elemental abundance pattern and roughly “normal” isotopic ratios. HL, consisting of isotopically anomalous Xe‐HL and Kr‐H, Ar with high 38Ar/36Ar, and most of the gas making up Ne‐A2 and He‐A, is released between 1100 °C and 1600 °C. HL has “planetary” elemental ratios, except that it has much more He and Ne than other known “planetary” components. HL gases are carried in the bulk diamonds, not in some trace phase. P6 has a slightly higher median release temperature than HL and is not cleanly separated from HL by stepped pyrolysis. Our data suggest that P6 has roughly “normal” isotopic compositions and “planetary” elemental ratios. Both P3 and P6 seem to be isotopically distinct from P1, the dominant “planetary” noble‐gas component in primitive chondrites. Release characteristics suggest that HL and P6 are sited in different carriers within the diamond fractions, while P3 may be sited near the surfaces of the diamonds.We find no evidence of separability of Xe‐H and Xe‐L or other isotopic variations in the HL component. However, because ∼1010 diamonds are required to measure a Xe composition, a lack of isotopic variability does not constrain diamonds to come from a single source. In fact, the high abundance of diamonds in primitive chondrites and the presence of at least three distinct noble‐gas components strongly suggest that diamonds originated in many sources. Relative abundances of noble‐gas components in diamonds correlate with degree of thermal processing (see companion paper), indicating that all meteorites sampled essentially the same mixture of diamonds. That mixture was probably inherited from the Sun's parent molecular cloud.