Biomodified Lupine Wholemeal Protein Isolates as a Source for High-Quality Protein and Applications for Nutraceuticals Preparation

Objectives This study aimed to formulate a nutraceuticals in chewable form using biomodified lupine wholemeal protein isolates as a source of high protein content and grapefruit essential oil (Citrus paradise) for beany taste masking in combination with a low-calorie and low-glycemic index sweetener xylitol, and citric acid. Materials and Methods Lupine wholemeal (LW) seeds Lupinus luteus and L. angustifolius varieties, including newly bred in Lithuania hybrid lines were obtained from the Lithuanian Institute of Agriculture (Vilnius, Lithuania). Prior to fermententation with Latilactobacillus sakei strain, lupine seeds underwent milled to achieve a consistent particle size (2 mm) by using a laboratory mill (Braun, Germany). For the fermentation were used submerged (SubF) and solid-state (SoF) fermentation conditions. The milled LW were mixed with water and L. sakei suspension, and fermented for 48 hours (30±2°C). Final moisture content in the LW was 45% for SoF and 65% for SubF conditions. Non-fermented LW was analysed as a control samples. Following fermentation, proteins were isolated from the LW using an alkaline extraction method. Finally, for the production of nutraceuticals was selected ‘Vilniai‘ lupine variety, and its protein isolates were incorporated into various nutraceutical formulations at different concentrations. Results The ‘Vilniai‘ variety of lupine protein, fermented with L. sakei (SubF conditions), was selected for nutraceuticals preparing due to its high protein content (≤ 90%). Also, demonstrated the highest protein digestibility (89.94±0.87%), and minimal amounts of antinutritional factors, such as trypsin inhibitor (19.40± 0.48%), compared with other protein isolates. In addition, the combination of xylitol and ascorbic acid enchaced the overall acceptability (108.7±2.9), and texture firmness (0.7 mJ) of the nutraceuticals. The grapefruit essential (GEo) oil effectively masked undesirible beany taste associated with lupine protein, leading to a significant improvement in overall acceptability (93.6 score), while the addition of GEo increased the score to 125.7. Conclusions This study demonstrated that fermentation with L. sakei strain enhanced the AA profile of LW, increasing most essential and non-essential AA. Overall, the chewable form nutraceutical formulation, comprising lupine protein isolates (≤ 13.0%), xylitol, and GEo (≤ 0.2%), exhibited desirable functional compounds, favorable texture, and high overall acceptability.