Protein structural changes during processing of vegetable feed ingredients used in swine diets: implications for nutritional value

Abstract

Protein structure influences the accessibility of enzymes for digestion. The proportion of intramolecular β-sheets in the secondary structure of native proteins has been related to a decrease in protein digestibility. Changes to proteins that can be considered positive (for example, denaturation and random coil formation) or negative (for example, aggregation and Maillard reactions) for protein digestibility can occur simultaneously during processing. The final result of these changes on digestibility seems to be a counterbalance of the occurrence of each phenomenon. Occurrence of each phenomenon depends on the conditions applied, but also on the source and type of the protein that is processed. The correlation between denaturation enthalpy after processing and protein digestibility seems to be dependent on the protein source. Heat seems to be the processing parameter with the largest influence on changes in the structure of proteins. The effect of moisture is usually limited to the simultaneous application of heat, but increasing level of moisture during processing usually increases structural changes in proteins. The effect of shear on protein structure is commonly studied using extrusion, although the multifactorial essence of this technology does not allow disentanglement of the separate effects of each processing parameter (for example, heat, shear, moisture). Although most of the available literature on the processing of feed ingredients reports effects on protein digestibility, the mechanisms that explain these effects are usually lacking. Clarifying these mechanisms could aid in the prediction of the nutritional consequences of processing conditions.

Effects of Fermentation on the Quality, Structure, and Nonnutritive Contents of Lentil (Lens culinaris) Proteins

“…However, the extent of this shift in this study was greater than that in the study by Wang et al [39] and Yasar et al [14]. Consequently, the effects of bacterial fermentation on secondary protein components were more beneficial than those of industrial food processes involving extreme heating and pressure treatment conditions, such as cooking, extrusion, and pelleting [40].…”

“…In this study, the magnitude of these modifications was substantial. Alterations are significantly associated positively with enhanced protein quality [40].…”

“…e increase in the digestibility of fermented LPs was proven in this study. In addition, a decrease in the α-helix: β-sheet ratio is related to enhancing intestinal protein digestibility [40]. e α-helix: β-sheet ratio decreased from 59.77 to 29.42% on day 2 and continuously decreased to 26.00% on day 3.…”

Plant protein ingredients with food functionality potential

“…2015; Salazar‐Villanea et al . 2016). Indeed, the variation between protein ingredients from the same source extracted with different methods may be greater than the variation between protein ingredients from different sources extracted in the same way (Nicolai & Chassenieux 2019).…”

A Fast and Robust FTIR-ATR Coupled Chemometric Determination of Chemical and Molecular Structure of Wheat (Triticum aestivum L.) under a Series of Microbial Fermentation Processes

“…In the above study, a univariate statistical analysis was used to qualitatively quantify the differences in chemical and molecular structure between the fermented and unfermented sample of barley. It was previously well documented that the protein quality can be improved in the form of changed SPC by food processing (Salazar-Villanea et al, 2016). Changing SPC can increase the accessibilities of enzymes during in vitro or in vivo protein digestion (Salazar-Villanea et al, 2016).…”