Beeswax, candelilla wax, carnauba wax, and a high-melting fraction of anhydrous milkfat were homogenized with whey protein to produce edible emulsion films. Lipid type and amount were important in controlling the emulsion film water vapor permeability (WVP). The WVPs of the beeswax and milkfat emulsion films were significantly lower than that of films from lower moisture transmitters, carnauba and candelilla wax. Lipid WVP and degree of viscoelasticity determined the barrier properties of the films. A significant reduction in WVP of whey protein films could be achieved using large volume fractions of lipid depending on lipid type.

Generally referred to as polyphenols (PPs), beer flavonoids such as the flavan-3-ols and their condensed products, the proanthocyanidins, represent a class of readily oxidizable compounds capable of hindering or preventing the oxidation of other molecules present in beer. Flavan-3-ol and proanthocyanidin capacity to improve oxidative stability has been well established in other food systems, and thus these antioxidants have recently gained significant consideration as potential beer flavour modifiers and/or stabilizers. The duality of their presence in beer is that PPs complex with proteins in the beer matrix to form temporary and permanent hazes. Undesirable physical instability caused by PP-protein interactions can be resolved via use of adsorptive resins such as polyvinylpyrrolidine. While there is no doubt that polyphenol removal increases beer shelf stability in terms of haze formation, the impact of polyphenol removal on beer flavour remains unresolved. This review discusses the sources, content and impact of polyphenol presence and removal on beer physical and flavour stability.

The rate of isomerization of alpha acids to iso-alpha acids (the compounds contributing bitter taste to beer) was determined across a range of temperatures (90-130 degrees C) to characterize the rate at which iso-alpha acids are formed during kettle boiling. Multiple 12 mL stainless steel vessels were utilized to heat samples (alpha acids in a pH 5.2 buffered aqueous solution) at given temperatures, for varying lengths of time. Concentrations of alpha acids and iso-alpha acids were quantified by high-pressure liquid chromatography (HPLC). The isomerization reaction was found to be first order, with reaction rate varying as a function of temperature. Rate constants were experimentally determined to be k1 = (7.9 x 10(11)) e(-11858/T) for the isomerization reaction of alpha acids to iso-alpha acids, and k2 = (4.1 x 10(12)) e(-12994/T) for the subsequent loss of iso-alpha acids to uncharacterized degradation products. Activation energy was experimentally determined to be 98.6 kJ per mole for isomerization, and 108.0 kJ per mole for degradation. Losses of iso-alpha acids to degradation products were pronounced for cases in which boiling was continued beyond two half-lives of alpha-acid concentration.

Physical processing with or without enzyme treatments on protein extraction from heat-stabilized defatted rice bran (HDRB) was evaluated. Freeze-thaw, sonication, high-speed blending, and high-pressure methods extracted 12%, 15%, 16%, and 11% protein, respectively. Sonication (0-100%, 750 W), followed by amylase and combined amylase and protease treatments, extracted 25.6-33.9% and 54.0-57.8% protein, respectively. Blending followed by amylase and protease treatment extracted 5.0% more protein than the nonblended enzymatic treatments. High-pressure treatments, 0-800 MPa, with water or amylase-protease combinations, extracted 10.5-11.1% or 61.8-66.6% protein, respectively. These results suggest that physical processing in combination with enzyme treatments can be effective in extracting protein from HDRB.

The activity of chymosin, plasmin, and Lactococcus lactis enzymes (cell envelope proteinase, intracellular peptidases, and glycolytic enzymes) were determined after 5-min exposures to pressures up to 800 MPa. Plasmin was unaffected by any pressure treatment. Chymosin activity was unaffected up to 400 MPa and decreased at 500 to 800 MPa. Fifty percent of control chymosin activity remained after the 800 MPa treatment. The lactococcal cell envelope proteinase (CEP) and intracellular peptidase activities were monitored in cell extracts of pressure-treated cells. A pressure of 100 MPa increased the CEP activity, whereas 200 MPa had no effect. At 300 MPa, CEP activity was reduced, and 400 to 800 MPa inactivated the enzyme. X-Prolyl-dipeptidyl aminopeptidase was insensitive to 5-min pressure treatments of 100 to 300 MPa, but was inactivated at 400 to 800 MPa. Aminopeptidase N was unaffected by 100 and 200 MPa. However, 300 MPa significantly reduced its activity, and 400 to 800 MPa inactivated it. Aminopeptidase C activity increased with increasing pressures up to 700 MPa. High pressure did not affect aminopeptidase A activity at any level. Hydrolysis of Lys-Ala-p-NA doubled after 300-MPa exposure, and was eliminated at 400 to 800 MPa. Glycolytic enzyme activities of pressure-treated cells were evaluated collectively by determining the titratable acidity as lactic acid produced by cell extracts in the presence of glucose. The titratable acidities produced by the 100 and 200 MPa samples were slightly increased compared to the control. At 300 to 800 MPa, no significant acid production was observed. These data demonstrate that high pressure causes no effect, activation, or inactivation of proteolytic and glycolytic enzymes depending on the pressure level and enzyme. Pressure treatment of cheese may alter enzymes involved in ripening, and pressure-treating L. lactis may provide a means to generate attenuated starters with altered enzyme profiles.

A kinetic study of pectinmethylesterase (PME) inactivation in orange juice was conducted. Juice samples were subjected to combinations of high pressure (400, 500, 600 MPa) and thermal (25, 37.5, 50 8C) treatments for various time periods. PME inactivation followed a first-order kinetic model with a residual activity of pressureresistant enzyme remaining. Calculated D-values ranged from 4.6 min to 117.5 min at 600 MPa/50 8C and 400 MPa/25 8C, respectively. Pressures in excess of 500 MPa resulted in sufficiently fast inactivation rates for economic viability of the process.

Dry‐hopping is a technique that has been used by brewers to increase the hop aroma and flavour of beer for centuries. Throughout the twenty first century, dry‐hopping has become an increasingly popular method among craft brewers to impart intense hoppy aroma and flavour to beer. Many US craft brewers use extremely high dry‐hop dosing rates of up to 2200 g/hL and this is both unsustainable and potentially wasteful. This study examines the impact of dry‐hopping rate on the sensorial and analytical characteristics of dry‐hopped beers. An unhopped pale beer was statically dry‐hopped with whole cone Cascade from the 2015 harvest over a broad range of dry‐hopping rates (200–1600 g/hL) in replicated, pilot scale (80 L) aliquots. Trained panellists using descriptive analysis scaled the overall and qualitative hop aroma intensity of these beers, as well as the unhopped base beer. Instrumental analysis was used to measure the levels of hop volatile and non‐volatile extraction between the treatments. The relationship between dry‐hopping rate and the sensorial and analytical characteristics of the finished beer was not linear and, based on the extraction efficiencies of select hop volatiles, had an ideal range between 400 and 800 g/hL. © 2018 The Institute of Brewing & Distilling

Several process alternatives for the stabilization of fresh orange juice at pressures between 500 MPa and 800 MPa and temperatures between 25 and 50 8C were evaluated. Processing at 800 MPa and 25 8C for 1 min and use of thermally pasteurized pulp yielded the lowest level of residual pectinmethylesterase activity (3.9%) and good cloud stability at 4 and 37 8C over a period of more than 2 mo. Ascorbic acid loss was less than 20% after storage for 3 mo at 4 8C or 2 mo at 15 8C. Color values were stable during storage at 4, 15, and 26 8C.