Melting, Crystallization, and In Vitro Digestion Properties of Fats Containing Stearoyl-Rich Triacylglycerols

Fats containing the stearoyl-rich triacylglycerols (TAGs) of 1,2-distearoyl-3-oleoylglycerol (SSO) and 1,3-dioleoyl-2-stearoylglycerol (OSO) were synthesized via the lipase-catalyzed acidolysis of tristearin (SSS)-rich fat and oleic acids, followed by solvent fractionation. Their physicochemical properties and in vitro digestibilities were compared. The SSS-, SSO-, and OSO-rich fats comprised 81.6%, 52.9%, and 33.1% stearic acid, respectively, whereas oleic acid comprised 2.9%, 37.5%, and 56.2%, respectively. The SSS-, SSO-, and OSO-rich fats contained the TAGs of SaSaSa (100.00%), SaSaMo (86.98%), and MoSaMo (67.12%), respectively, and the major TAGs were SSS, SSO, and OSO, respectively. Melting and crystallization temperatures were higher and fat crystals were larger and densely packed in the descending order of SSS-, SSO and OSO-rich fats. Both in vitro multi-step digestion and pH-stat digestion were more rapid for OSO- than SSO-rich fat. Oleic acid was digested faster than stearic acid during the initial digestion, then the rate decreased, whereas that of stearic acid increased over prolonged digestion. Fats that were richer in stearoyl at the sn-1,3 position of TAG melted and crystallized at higher temperatures, had a densely packed microstructure of large fat crystals and were poorly digested. Stearic acid imparts the essential physical attributes of melting and crystallization in solid fats, and the low digestible stearoyl-rich fat would be a viable substitute for trans fatty acids in food lipid industry.

Regiospecific Positioning of Palmitic Acid in Triacylglycerol Structure of Enzymatically Modified Lipids Affects Physicochemical and In Vitro Digestion Properties

Tripalmitin-(PPP, 81.2%), 1,3-dipalmitoyl-2-oleoylglycerol-(POP, 64.4%), 1,2-dipalmitoyl-3-oleoylglycerol-(PPO, 86.5%), and 1,3-dioleoyl-2-palmitoylglycerol-(OPO, 50.2%)-rich lipids with different regiospecific positions of palmitic acid (P) were synthesized via acetone fractionation and lipase-catalyzed acidolysis, and their physicochemical and hydrolytic characteristics were compared. Triacylglycerols (TAGs) with higher content of P, wherein P was at the sn-1 (or 3) position, had higher melting points, crystallization temperatures, and packing densities of fat crystals compared to those with a lower content of P, and with P at the sn-2 position. The in vitro digestion degree calculated as released fatty acid (FA) (%) at 30, 60, and 120 min was in the following order: OPO-rich > PPO-rich > POP-rich lipids. At 120 min, in vitro digestion of the OPO-rich lipid released 92.6% of fatty acids, resulting in the highest digestibility, while 89.7% and 87.2% of fatty acids were released from the OPO-rich and PPO-rich lipids, respectively. Over the digestion period, the TAG and monoacylglycerol (MAG) contents decreased, while the diacylglycerol (DAG) content initially increased and then decreased, and the 1,2-DAG content exceeded the 1,3-DAG content. Therefore, the content and stereospecific position of P attached to a specific TAG affected the physicochemical and in vitro digestion characteristics of the lipids.

Intermittent dynamics of bubble dissolution due to interfacial growth of fat crystals

Foams are inherently unstable objects, that age and disappear over time. The main cause of foam aging is Ostwald ripening: smaller air bubbles within the foam empty their gas content...

Scientifically based production criteria for chocolate semi-finished products using fruit and vegetable powders

Chocolate glaze consists mainly of sugar (50%) and fat (35%) and is a high-calorie semi-finished product with a high content of simple carbohydrates. The standard for glaze provides the possibility of producing chocolate glaze with fruit and vegetable components, which reduces the content of simple carbohydrates. Studied and justified the criteria for the production of chocolate glazes with different contents of fruit and vegetable powders. Analysis of the rheological parameters of chocolate semi-finished products showed that the introduction of fruit and vegetable powder instead of part of the sugar leads to a significant change in the nature of the rheological behavior of the semi-finished product. The yield strength increases from 3.4 to 12.6 Pa as the proportion of fruit and vegetable powder in the formulation increases. In order to determine the effect of the production method on changes in the yield strength of fruit and vegetable chocolate glaze, a series of experiments was carried out. It was found that with a constant content of fruit and vegetable powder (11%), temperature, processing time and machine support, the resulting chocolate glazes differed in their rheological characteristics. It was found that the greatest reduction in the yield strength of fruit and vegetable chocolate glazes during the production process can be achieved by stage-by-stage grinding of the formulation components in a ball mill and the additional introduction of PGPR emulsifier at the conching stage. The quality of chocolate semi-finished products depends not only on rheological parameters, but also on crystallization properties. The developed chocolate glazes with different contents of the fruit and vegetable component were processed at a temperature of about 30 °C in a laboratory tempering machine in order to form and stabilize fat crystals in ?-form. Then, the temperindex was determined. It was found that, subject to the same tempering conditions, with an increase in the proportion of fruit and vegetable powder, the temperature of glazes increases. Glazes with a mass fraction of fruit and vegetable powder of more than 7% were distinguished by the properties of re-tempered semi-finished products - the presence of large fat crystals, a rough structure and the absence of surface gloss. In order to obtain the optimal temperature index of glazes with a content of fruit and vegetable raw materials of more than 7%, their tempering modes were developed.