Berry fruit by-products are a source of polyphenol compounds and highly nutritious oils and can be reused to fulfill the requirements of the circular economy model. One of the methods of obtaining polyphenol-rich extracts or oils is extraction. Applying conventional solvent extraction techniques may be insufficient to reach high polyphenol or lipid fraction yields and selectivity of specific compounds. Alternative extraction methods, mainly ultrasound-assisted extraction, pulsed electric field-assisted extraction, microwave-assisted extraction and supercritical fluid extraction, are ways to improve the efficiency of the isolation of bioactive compounds or oils from berry fruit by-products. Additionally, non-conventional techniques are considered as green extraction methods, as they consume less energy, solvent volume and time. The aim of this review is to summarize the studies on alternative extraction methods and their relationship to the composition of extracts or oils obtained from berry waste products.

The aim of this study was the analytical evaluations of human milk fat substitutes (HMFS) synthesized via enzymatic interesterification of lard and milk thistle oil mixtures by a immobilized commercial sn-1,3-specific lipase, using calorimetric and chromatographic methods. The mixtures of lard and milk thistle oil at mass ratio 6:4 and 8:2 were interesterified for 2, 4 and 6 h at the temperature of 60 °C. The determination of fatty acid composition was carried out by gas chromatographic analysis of fatty acid methyl esters. The positional distribution of fatty acids in the sn-2 and sn-1,3 positions of triacylglycerols was based on the ability of the pancreatic lipase to selectively hydrolyze ester bonds in the sn-1,3 positions. Pressure differential scanning calorimetry (PDSC) method was used for the determination of the oxidative stability of HMFS. The oxidative induction time was obtained from the PDSC curves. Due to enzymatic interesterification of mixtures of lard and milk thistle oil, new HMFS that have a similar regiospecific structure of triacylglycerols to human milk fat can be produced. The induction time obtained from PDSC measurements can be used as a parameter for the assessment of the resistance of tested fats to their thermal-oxidative decomposition.

A relatively unexplored goat’s milk fat and goat’s milk chocolate were investigated to enhance thermal properties of both. Differential scanning calorimetry, pressure differential scanning calorimetry and thermogravimetry were successfully used to determine polymorphic forms of goat’s milk fat, oxidative stability and the percentage composition of goat’s milk chocolate. The thermal profile and characteristic of the goat’s milk chocolate showed parameters very similar to dark chocolate. Significant differences were found in the induction times of goat milk fat and fat extracted from goat’s chocolate. For the goat’s milk fat, the value of activation energy (E_a) for a maximum temperature was almost identical to the E_a value obtained by the means of onset temperature. However significant difference was observed between values of E_a for the fat extracted from goat’s milk chocolate.

Cranberry pomace considered as a by-product of fruit industry contains seeds which may be processed to highly nutritive oil. Conventional extraction methods may be, however, harmful to natural environment, thus alternative, ultrasound-assisted extraction method may be useful tool to reduce environmental impact. In the following study, sonication was applied to extract oil from cranberry seeds. The aim of the study was to determine the most efficient conditions of ultrasound-assisted extraction of oil and to investigate sonication influence on the properties of final product. Ultrasound amplitude and extraction time were independent variables; yield and maximum induction time of oils were responses. The most efficient conditions were amplitude of 95% and extraction time of 11.38 min. Model predicted extraction yield of 22.55 ± 0.36% (vs. actual 21.98 ± 0.08%) and induction time of 52.60 ± 0.95 min (vs. actual 61.95 ± 3.06 min). Detailed analyses of oil extracted in the most efficient conditions and the control sample were performed. Kinetic parameters of oil oxidation, fatty acid profile and distribution, melting characteristics studies were carried out. Sonication influenced activation energy of oxidation reaction, contribution of chosen fatty acids (oleic, α-linolenic and eicosenoic fatty acids) and distribution of oleic and α-linolenic fatty acids in sn-2 position of triacylglycerols. Slight changes in melting profile of oils were also recorded. Scanning electron microscopy of cranberry seeds revealed that ultrasound treatment resulted in pore enlargement and fat agglomeration damage. Additional studies of thermal properties of cranberry seeds: differential scanning calorimetry and modulated differential scanning calorimetry were performed, which confirmed that cranberry seeds may be a new source of oil with unique properties.