Evaluation of Models for Temperature-Dependent Viscosity Changes in Dairy Protein Beverage Formulations During Thermal Processing

Improving physicochemical, rheometry and sensory attributes of fortified beverages using jujube alcoholic/aqueous extract loaded Gellan-Protein macrocarriers

The use of phenolic bioactive substances in beverages is introduced by novel techniques as a functional food product. Gel beads from jujube extract were prepared by extrusion method using encapsulation and coated by whey protein isolate and soy protein isolate and thus, a functional beverage was prepared from these beads. There were three types of beads, including Gellan, Gellan/whey protein isolate and Gellan/soy protein isolate. The pH, acidity, Brix, turbidity, viscosity and sensory properties were evaluated. Observing the increase in pH is the result of the release of small amounts of fruit extract, the effect of which can be seen in the inverse relationship of acidity next to pH. The results demonstrate that the highest viscosity is related to protein beverages, especially Gellan gum/SPI beads' beverage. Hence, the highest turbidity in Gellan gum/SPI beads' beverage was visible on the 14th day (66.6 NTU). Thereby, there is potential for these Gellan beads beverages with suitable sensory scores to be wholly utilized and developed with the aim of this study. Along with it, this new beverage can attract the opinion of a wide range of consumers. Therewith, the industrialization of such types of products helps to improve the consumer market.

Physical and sensory properties of lemon-flavored acidic beverages formulated with nonfat dry milk during storage

Sensory and physical properties of 2 lemon-flavored beverages with 5% and 7.5% wt/wt nonfat dry milk (NFDM) at pH 2.5 were studied during storage. The 2 beverages had similar volatile compounds, but the 5% NFDM had higher aroma and lemon flavor, with a preferred appearance by consumers due to the lower turbidity and viscosity. After 28 d of storage at 4°C, lemon flavor decreased in the 5% NFDM beverage but was still more intense than the 7.5% one. During 70 d of storage, no microorganisms were detected, and the beverages were more stable when stored at 4°C than at room temperature according to changes of physical properties measured for appearance, turbidity, color, particle size, zeta potential, rheological properties, and transmission electron microscopy morphology. Findings of the present study suggest that NFDM may be used at 5% wt/wt to produce stable acidic dairy beverages with low turbidity when stored at 4°C.

Effect of long-term heat exposure on rheological and intrinsic water characteristics of bone-derived beef stocks

Bone-derived protein stocks are used in food industry to enhance taste of soups, sauces, and a range of other products. Both during commercial manufacturing and when used for culinary purposes, the stocks may be exposed to high temperatures for an extended time period. The present study investigated the effect of retention at 90°C for 0, 3, 6, 9, 24, 48, 72, and 168 hr on the functional attributes of concentrated bone-derived beef stocks (57% Dry matter (DM)). Visual inspection and rheological analyses showed that during increasing heat exposure, the gel strength as well as viscosity of the concentrated stocks decreased incrementally and significantly (P > 0.001). Nuclear magnetic resonance (NMR) relaxation measurements conducted on the beef stocks also revealed strong effects of heat exposure on the transverse (T₂ ) relaxation time, which increased incrementally and significantly (P > 0.001) with longer heat exposure. Thus, the present study demonstrated that heat-induced changes in rheological properties of bone-derived beef stocks can be ascribed to changes in intrinsic water-protein interactions and water attributes as a result of heat-induced protein modifications. In conclusion, the study proves that NMR relaxometry is a valuable tool for monitoring changes in intrinsic water mobility that are manifested in modified functional attributes of concentrated beef stocks.

Processing raspberry-flavored whey drink using ohmic heating: Physical, thermal and microstructural considerations

The effect of ohmic heating processing (10, 100, 1000 Hz - 25 V;45, 60, 80 V - 60 Hz until 65 °C-30 min) on physical (color, rheology, particle size diameter), thermal (differential scanning calorimetry, DSC), physicochemical (time domain nuclear magnetic resonance, TD-NMR) and microstructural (optical microscopy) properties of raspberry-flavored whey drink was investigated. The samples were submitted to an ohmic system and conventional pasteurization (65 °C-30 min). Both processing led to increases in the color parameters (C*, h* and ∆E*) in the first 30 min. For the treatments, 10 Hz-25 V and 1000 Hz-25 V, more viscous, and consequently increased D[4,3] and D[3,2] values were observed, and similar results were obtained for the DSC behavior. The microstructure confirmed aggregation of cell structure in those configurations (10 Hz and 1000 Hz-25 V). OH, parameters for both ohmic configurations have an impact in all the evaluated parameters for raspberry-flavored whey drink, which can be interesting for the dairy industry.

Non-contact optical hand-held viscosity sensor with incident angle and irradiation timing controls

This paper proposes a novel optical hand-held viscosity sensor based on a laser-induced capillary wave method that can be used as a noncontact and quick in situ viscometry of liquid samples. Incident angle and irradiation timing control systems were integrated into the hand-held viscosity sensor to robustly measure viscosity by detecting the optical signal in a hand-held condition. We report the stability evaluation of these systems under the hand-held condition. Finally, the proposed sensor's applicability to the hand-held viscometer was confirmed by measuring the viscosity distribution that the temperature gradient of the liquid sample caused.