Primary nucleation of alpha-lactose monohydrate: The effect of supersaturation and temperature

Crystallization of Lactose-Protein Solutions in the Presence of Flavonoids

Lactose is commonly crystallized in the presence of whey proteins, forming co-crystals of lactose and proteins. This work hypothesized that flavonoids such as rutin or epigallocatechin-3-gallate (EGCG) could be incorporated into the lactose and protein co-crystal structure since flavonoids may interact with both lactose and proteins. The interactions between whey proteins and flavonoids were first studied. Then, lactose-protein solutions were crystallized with and without flavonoids, measuring the kinetic parameters of crystallization and characterizing the resulting crystals. The incorporation of flavonoids in lactose-protein co-crystals depended on the hydrophilic nature of flavonoids. The hydrophilic EGCG was scarcely enclosed in the crystal lattice of lactose and avoided the inclusion of whey proteins in the crystals. In contrast, the less water-soluble rutin interacted with whey proteins and lactose, leading to the formation of co-crystals containing lactose, protein, and a large concentration of rutin (3.468 ± 0.392 mg per 100 mg of crystals).

THE STUDY OF LOW-LACTOSE MILK WHEY STRUCTURE AND MODEL SYSTEMS ON ITS BASIS

This study developed a technology of low-lactose semi-finished products, based on fermented whey and pumpkin pulp puree, and offered a possibility of its use in the technology of structured culinary products. This research carried out the required substantiation of the methods of preliminary processing of raw materials, and studied the technological properties and structure of model compositions with their use. During the experiment, a number of studies were carried out, which substantiated the method and modes of condensation of whey, and provided a comparative analysis of the homogeneity of lactose-free and lactose-containing samples of whey under various modes of condensation. The study obtained the results of calculations of the equivalent diameter of the studied samples of lactose-containing and low-lactose whey, condensed by the contact method and in vacuum. It was found, that the structure is homogeneous at a number average crystal diameter of up to 5 μm. The restriction is valid for CLLWV with a calculated diameter of about 3.84 μm with a coefficient of variation of 1.35 % with an increase of 10,000 times. The study revealed the alternation of smooth and granular sections of the micron level (0.1 ... 5 μm) in the structure of the studied low-lactose semi-finished product with an increase of 300 times. It was determined, that the extremum of the differential curve of the particle size distribution of CLLWV corresponds to the number average crystal diameter of 3.84 μm. It was established, that the most homogeneous fractional composition is inherent in the studied sample of CLLWV, for which the values of fraction diameters are in the range from 1.46 μm to 4.96 μm. The optimal ratio of the components of the model CLLWV: FPPP system was determined as 70 % to 30 % respectively. With this composition, the model system is characterized by the formation of protein-pectin complexes, which is confirmed by microscopy with a magnification of 90 times

An exploration of the solvent- and acid-catalyzed mutarotation mechanisms of lactose in aqueous solution

Exploration of the solvent- and acid-catalyzed mutarotation mechanisms of lactose to reveal the ease of the mutarotation varying with the acidity of the catalyst.

Disposal of high-arsenic waste acid by the stepwise formation of gypsum and scorodite

The typical disposal of high-arsenic waste acid is at the expense of discharging a large quantity of hazardous solid waste, resulting in secondary pollution of arsenic. We propose a modified lime/ferric salt method for high-arsenic waste acid disposal by the stepwise formation of gypsum and scorodite at atmospheric pressure. The sulfuric acid in the high-arsenic waste acid is first removed by calcium carbonate generating gypsum, and then the arsenic in the solution is precipitated in form of scorodite. Gypsum with an arsenic leaching concentration below 5 mg L⁻¹ is obtained at a final pH of 0.5 in the calcium carbonate neutralization stage. In the second stage, the optimal conditions including a starting pH of 2.0, an Fe/As ratio of 1.5, a reaction temperature in the range of 80–90 °C and a reaction time equal to or longer than 8 hours provide an arsenic removal efficiency of 95.34% by the formation of well-crystallized and environmentally stable scorodite with grain sizes in a range of 1–5 μm. The proposed process offers a promising and facile solution for the low-cost disposal of high-arsenic waste acid in the nonferrous metallurgical industry, which enables an efficient arsenic removal with the good accessibility of chemical reagents and facilities.

Arsenic is removed from high arsenic waste acid via the stepwise formation of gypsum and scorodite.

Evaluating the crystallization of lactose at different cooling rates from milk and whey permeates in terms of crystal yield and purity

The cooling rate of supersaturated lactose solution is one of the important parameters determining the yield and size distribution of lactose crystals. The influence of increasing cooling rate on lactose crystallization and quality of lactose crystals was evaluated in concentrated solutions prepared from deproteinized whey powder (DPW) and milk permeate powder (MPP). Concentrated permeates (DPW and MPP) with 60% (wt/wt) total solids were prepared by reconstituting permeate powders in water at 80°C for 2 h for lactose dissolution. Three cooling rates, 0.04°C/min (slow), 0.06°C/min (medium), and 0.08°C/min (fast) were studied in duplicate. A common rapid cooling step (80 to 60°C at 0.5°C/min) followed by slow, medium, and fast cooling rates were applied as per the experimental design from 60 to 20°C. After crystallization, the crystal slurry was centrifuged, washed with cold water, and dried. The dried lactose crystals were weighed to calculate the lactose yield. Final mean particle chord lengths were measured at the end of crystallization using focused beam reflectance measurement for slow, medium, and fast cooling rates, and observed to be not significantly different for DPW (27-33 µm) and MPP (31-34 µm) concentrates. Similarly, the lactose yield for slow, medium, and fast cooling rates in the DPW and MPP concentrates were in the range of 71 to 73% and 76 to 81%, respectively, and no significant difference between the 3 cooling rates was found. Qualitative analysis of dried lactose crystals exhibited no noticeable differences in the crystal purity with increasing cooling rate. This study evaluated the possibility of reducing the crystallization times by 8 h compared with current industrial practice without compromising the crystal yield and quality.

Formation of tooeleite and the role of direct removal of As(III) from high-arsenic acid wastewater

In this study, an earth-mimetic method was proposed for the direct removal of As(III) by the formation of tooeleite, a ferric arsenite sulfate mineral. A series of batch experiments was used to study the relationship between the formation of tooeleite and the removal of As(III). The results indicate that As(III) removal efficiency reached up to 99% under the treatment condition of pH 1.8-4.5, initial As(III) concentration higher than 0.75g/L, and Fe/As ranged from 0.8 to 2 at room temperature. Various characterizations confirm that the precipitate obtained by this treatment was tooeleite with relatively high stability. In addition, it is assumed that ferrihydrite exists as a precursor, which is vital to the formation of tooeleite and the removal of As(III). This study suggests that tooeleite formation may be an alternative method in the direct removal of As(III) from high-arsenic acid wastewater.