Our objectives were to determine the effect of UF of skim milk at 7°C and 50°C on UF processing, lactose removal, mineral partitioning, and skim milk retentate physical, chemical, and sensory properties at 3 (3.4%, 7.5%, and 10.5%) protein concentration with 2 different heat processing treatments (HTST pasteurization and autoclave). Pasteurized skim milk was split into 2 portions, and the 7°C UF processing run was done on one day and the 50°C UF processing run was done on the next day. Skim milk was UF and diafiltered at 7°C and 50°C, and as permeate was removed, deionized water at 7°C or 50°C was added in an equal amount by weight, as permeate was removed to maintain constant protein concentration in the retentate during UF until 98% or more of lactose, and low-molecular-weight soluble milk components were removed. All skim milk-based beverage bases from the 7°C and 50°C UF of skim milk were HTST (78°C for 15 s) processed or autoclaved (116°C for 6 min). The physical, chemical, and sensory properties of all treatments were measured. This process was replicated twice with a new batch of pasteurized skim milk in a different week with the 7°C and 50°C UF processing runs done in reverse order. Overall, lactose-free skim milk at 3.4%, 7.5%, and 10.5% protein produced by UF with diafiltration (DF), was more bland, more white, and less heat stable (i.e., stable to retorting but not direct steam injection at 142°C for 2-3 s) than skim milk, based on both sensory scores and instrumental measures. A 98% to 99% removal of lactose from skim milk was achieved (final lactose concentration <0.06 g/100g) with a diafiltration ratio of water to milk of about 4 to 1 was used at both 7°C and 50°C. The processing time to achieve that lactose removal from the same starting weight of milk was about twice as long when filtering at 7°C than 50°C because of the lower flux (23 vs. 48 kg/m per hour). The continuous DF at constant protein concentration maintained constant flux for a processing time of 4 and 8 h at 50°C and 7°C, respectively. The final freezing point of the lactose and soluble mineral reduced milk was close to that of water (-0.015°C vs. -0.525°C for skim milk) and the pH of the lactose-free milk at 20°C increased from about 6.5 for skim to about 7.33 and 7.46 for UF with continuous DF of skim milk at 7°C and 50°C, respectively. Removal of compounds that absorb light (in the range of 360 to 500 nm) from milk in the permeate, increased light reflectance and whiteness and decreased yellowness relative to the starting skim milk.
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http://dx.doi.org/10.3168/jds.2023-24396 | DOI Listing |
Biotechnol Appl Biochem
December 2024
Department of Life Sciences, Hemchandracharya North Gujarat University, Patan, Gujarat, India.
Two marine-derived bacteria, Bacillus paralicheniformis (HR-1) and Bacillus haynesii (HR-5), were isolated from sediments and identified using 16S ribosomal RNA gene amplification and sequencing as well as biochemical analysis. The development of a bacterial consortium (HR-1 & HR-5) from these two bacteria was used to increase the production of the protease enzyme under various conditions, including fermentation media, carbon and nitrogen sources (1% w/v), different pH levels, incubation time, and the obtained enzyme, were detected using SDS-PAGE followed by purification. Bacterial consortium HR-1 & HR-5 exhibited maximum protease production (330.
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December 2024
Department of Food Engineering, Faculty of Engineering Ege University İzmir Turkey.
This study investigated the survival dynamics of BG24, a probiotic strain, within reconstituted skim milk (RSM) and yeast extract (YE) matrices during the spray-drying (SD) process, encompassing of inlet/outlet air temperatures. Notably, optimum SD parameters were found to be an inlet air temperature of 150°C and outlet air temperature of 83°C, that achieving high viability (92.23%), and reducing both moisture content (MC) (3.
View Article and Find Full Text PDFAppetite
December 2024
Division of Human Nutrition and Health, Wageningen University and Research, Wageningen, the Netherlands. Electronic address:
Reduction of food fat content often comes at the cost of sensory appeal. Given that odours can enhance various fat-related sensory characteristics, their use as fat substitutes seems promising. This cross-over study investigated whether sensory characteristics of a low-fat product (dairy milk) can be enhanced by the addition of a fat-related aroma (cream) and whether this influences subsequent eating behaviour within an ecologically valid scenario.
View Article and Find Full Text PDFFront Microbiol
December 2024
College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, China.
The enhancement of cellulose degradation is important for improving the quality of corn-stalk silage. However, the rapid drop in pH caused by the propagation of lactic acid bacteria (LAB) can influence the degradation of cellulose by cellulose-degrading microorganisms (CDMs) during the mixed fermentation process of ensilage. In this study, a CDM ( 2-4, BM 2-4) was isolated, and its lyophilization condition was studied.
View Article and Find Full Text PDFFoods
December 2024
Fonterra Research and Development Centre, Dairy Farm Road, Palmerston North 4442, New Zealand.
The amino acid (AA) content of multiple samples of various dairy powders was determined, providing a comprehensive evaluation of the differences in AA profiles attributable to distinct manufacturing processes. Products examined included whole milk powder (WMP), skim milk powder (SMP), cheese whey protein concentrate (WPC-C), lactic acid casein whey protein concentrate (WPC-L), high-fat whey protein concentrate (WPC-HF), hydrolyzed whey protein concentrate (WPH), whey protein isolate (WPI), and demineralized whey protein (D90). WMP and SMP exhibited broadly similar AA profiles, with minor differences likely due to the minimal milk fat protein content, which is nearly absent from SMP.
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