Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties

A comprehensive investigation of the use of freeze concentration appro aches for the concentration of fish protein hydrolysates

Fish protein hydrolysates (FPH) are inherently unstable in their liquid form, necessitating either freezing or dewatering for stabilization. Gentle methods such as freeze concentration can be used to remove water, this can be achieved by freezing water in solution by decreasing the bulk temperature below freezing point and separating pure ice crystals from concentrated solution. This approach serves as an alternative to techniques like evaporation and reverse osmosis for concentrating solutions that have high water content, significant nutritional value, and thermolabile compounds. This is crucial as many bioactive compounds degrade when exposed to elevated temperatures. Another notable advantage of this technology is its potential to reduce energy consumption by up to 40% when integrated into the FPH drying process. Although this technology is currently industrialized primarily for juices, it can achieve concentrations of up to 60°Brix and manage viscosities up to 400 mPa.s. Numerous studies have been dedicated to enhancing design and processes, leading to a 35% reduction in the system's capital cost and a 20% reduction in energy consumption. Moreover, freeze concentration can synergize with other concentration techniques, creating more efficient hybrid processes. This review aims to introduce freeze concentration as a superior option for preserving fish protein hydrolysates, enhancing their stability, and maintaining their nutritional and bioactive qualities.

Characterization of Fruit Sorbet Matrices with Added Value from Zizyphus jujuba and Stevia rebaudiana

Sorbets are healthy ice cream alternatives and desired frozen desserts by vegetarians and vegans. This study focuses on assessing the effects of sorbet recipe alteration through the addition of different percentages of Zizyphus jujuba powder. Stevia rebaudiana was used as a sugar substituent. A control sample and five variables were developed. Peaches from the “Laskava” (native Bulgarian) variety were used as the main ingredient. The new sorbet matrices were characterized based on their moisture and ash content, overrun, melting behavior, melting rate, water holding capacity, pH, nutritional data, soluble solids content, titratable acidity, vitamin C content, total phenolic content and antioxidant activity. The microbial load and CIELAB color of the sorbet alternatives was also evaluated. A sensory evaluation revealed the most preferred variant. Panelists evaluated the appearance (n = 6), aroma (n = 5), flavor (n = 5), mouthfeel (n = 7), and aftertaste (n = 5). The soluble solids content varied from 17.50 to 33.03%, the ash content from 0.36 to 5.21%, the moisture content from 63.77 to 80.21%. The studied sorbet matrices have an overrun in the range from 8.11 to 12.32%. Results showed that a potential for the development of peach sorbet matrices with added value and a reasonable consumer acceptability exists. Further research can perfect the recipe and provide a reference for other frozen desserts.