The Influence of Whey Protein Isolate on the Quality Indicators of Acidophilic Ice Cream Based on Liquid Concentrates of Demineralized Whey.

The use of liquid whey concentrates in the composition of ice cream, especially in combination with other powdered whey proteins, is limited due to their understudied properties. This article shows the main rheological and thermophysical characteristics of ice cream mixes, as well as color parameters, microstructure, analysis of ice crystals and quality indicators of ice cream during storage. The most significant freezing of free water (p ≤ 0.05) was observed in the temperature range from the cryoscopic temperature to -10 °C. The microscopy of experimental ice cream samples based on hydrolyzed whey concentrates indicates the formation of a homogeneous crystalline structure of ice crystals with an average diameter of 13.75-14.75 µm. Microstructural analysis confirms the expediency of using whey protein isolate in ice cream, which ensures uniform distribution of air bubbles in the product and sufficient overrun (71.98-76.55%). The combination of non-hydrolyzed whey concentrate and 3% whey protein isolate provides the highest stability to preserve the purity and color intensity of the ice cream during storage. The produced ice cream can be classified as probiotic (number of Lactobacillus acidophilus not lower than 6.2 log CFU/g) and protein-enriched (protein supply from 15.02-18.59%).

Study of Water Freezing in Low-Fat Milky Ice Cream with Oat ß-Glucan and Its Influence on Quality Indicators.

The work is devoted to the study of the functional and technological properties of oat ß-glucan in low-fat milky ice cream (2% fat) in comparison with the stabilization system Cremodan® SI 320. ß-glucan (0.5%) has a greater effect on the cryoscopic temperature of ice cream mixes than Cremodan® SI 320 in the same amount (decrease by 0.166 °C vs. 0.078 °C), which inhibits the freezing process of free water in ice cream during technological processing in the temperature range from -5 to -10 °C. Microscopy of ice cream samples after freezing and hardening shows the ability of ß-glucan to form a greater number of energy bonds due to specific interaction with milk proteins. Analysis of the microstructure of ice cream samples during 28 d of storage confirms the ability of oat ß-glucan to suppress the growth of ice crystals more effectively than Cremodan® SI 320. Oat ß-glucan gives ice cream a rich creamy taste, increases overrun and resistance to melting, which brings this type of frozen dessert closer to a full-fat analogue (10% fat).

The Rheological Properties and Texture of Agar Gels with Canola Oil-Effect of Mixing Rate and Addition of Lecithin.

This study aimed to determine the effect of different mixing rates and the addition of lecithin on the rheological mechanical, and acoustic properties of agar gels with the addition of canola oil. The mixing rate of the agar-oil mixture was changed from 10,000 to 13,000 rpm. Additionally, agar gels with the addition of lecithin from 1 to 5% were prepared. The frequency sweep test was used (at 4 and 50 °C) within the linear viscoelastic region (LVR) in oscillatory measurement. The agar-oil mixture was cooled from 80 to 10 °C, enabling the obtainment of the gelling temperature. Texture profile analysis (TPA) and compression tests, as well as the acoustic emission method, were applied to analyse the texture of the gels. The syneresis and stability of gels during storage were also measure. The increase in mixing rate in the case of agar gel with canola oil causes an increase in the elastic component of materials as well hardness and gumminess. Also, samples prepared with the higher mixing rate have more uniform and stable structures, with small bubbles. The increase in the concentration of lecithin is ineffective due to the formation of gels with a weak matrix and low hardness, gumminess, and stability during storage.

The Effect of Composition, Pre-Treatment on the Mechanical and Acoustic Properties of Apple Gels and Freeze-Dried Materials.

This study aimed to determine the effect of the addition of apple juice concentrate (AJC) on the properties of agar gel and dried materials. Agar gels with the addition of apple juice concentrate in the range of 5-20% were prepared with or without the addition of maltodextrin. The gels were also soaked in the solution of AJC. The water content, water activity, densities, some mechanical and acoustic descriptors of gels, and the freeze-dried gels were analysed. The porosity and shrinkage of dried products were also investigated. The addition of AJC significantly changed mechanical and acoustic properties of gels. The hardness of gels decreased with a higher addition of concentrate. Dried samples with a lower concentration of sugars (the lower addition of AJC) were characterised by lower shrinkage and higher porosity, as well as crispness and glass transition temperature. The investigated mechanical and acoustic properties of dried gels showed the addition of apple concentrate at the level of 5% to agar solution was optimal.

Effect of Addition of Chokeberry Juice Concentrate and Foaming Agent on the Physical Properties of Agar Gel.

This study aimed to determine the effect of the addition of chokeberry juice concentrate (CJC) and foaming agent (egg albumin) with different percentages on the selected physical properties of agar gel. The agar gels with the addition of 5, 10, and 20% concentrations of chokeberry juice concentrate and with fructose addition were prepared. In addition, the foamed gels with different concentrations of egg albumin (in the range 0.5-2.0%) and CJC were produced. The water content, colour, density, hold-up and some mechanical and TPA (Texture Profile Analysis) descriptors as well some structural and acoustic emission parameters of non-aerated and foamed gels were analysed. The addition of CJC changed the colour of agar gel with fructose, the attractive appearance of the aerated gel was also linked with the addition of concentrate. The addition of 20% of CJC and foaming agent created samples with very low hardness, cohesiveness, and gumminess, and the structure of the aerated samples was characterised by the larger bubble diameter and the wider distribution of their size. The more promising texture and structure properties were obtained for samples with aerated gels with 5 and 10% addition of chokeberry juice concentrate.

The impact of ι- and κ-carrageenan addition on freezing process and ice crystals structure of strawberry sorbet frozen by various methods.

The aim of this work was to study the influence of ι- and κ-carrageenan addition to strawberry sorbet prepared by various freezing methods (cryostat and conventional freezer) on freezing kinetics and ice crystals structure. Four variants of strawberry-based sorbet were prepared: with no additive, with 0.1% addition of ι- and κ-carrageenan, and 1:1 blend of both. Freezing curves and freezing time, as well as the size and morphology of ice crystals, were analyzed. The addition of carrageenan stabilizers resulted in freezing process elongation. Reference samples were characterized by different dynamics of the freezing process. The addition of carrageenan increased the final temperature of the samples, compared to the reference sample (even 2.6 °C of difference). Additives reduced ice crystals growth. The most efficient was mixture of both fractions of carrageenan--the samples in this variant frozen in conventional freezer were characterized by the smallest ice crystals diameter--average 5.44 µm, while for the reference sample it was 17.79 µm. PRACTICAL APPLICATION: This research can give a new path for the carrageenan's hydrolysates application--not only for dairy products. Iota carrageenan fraction was recommended for dairy products according to its water-holding capacity in the presence of calcium ions. This study showed that mix of ι- and κ-carrageenan could bring positive results to such product as sorbet without any milk proteins addition. This experiment data could also be helpful when optimizing frozen desserts production in small gastronomy--especially the temperature and time of freezing modifications.

Characteristics of Instrumental Methods to Describe and Assess the Recrystallization Process in Ice Cream Systems.

Methods of testing and describing the recrystallization process in ice cream systems were characterized. The scope of this study included a description of the recrystallization process and a description and comparison of the following methods: microscopy and image analysis, focused beam reflectance measurement (FBRM), oscillation thermo-rheometry (OTR), nuclear magnetic resonance (NMR), splat-cooling assay, and X-ray microtomography (micro-CT). All the methods presented were suitable for characterization of the recrystallization process, although they provide different types of information, and they should be individually matched to the characteristics of the tested product.