Pine nut skin as a source of phytosterols and alkanediols - Hypocholesterolemic potential and development of sustainable vegan emulsifiers

Pine nut skin is a byproduct arising from the pine nut industry, whose composition and bioactive potential are currently unexplored. For this purpose, its characterization is required for the development of sustainable food ingredients.Pine nut skin was separated into finer (<500 μm) and coarser (≥500 μm) fractions, composed of carbohydrates (35 g/100 g and 11 g/100 g, respectively), lignin (47 g/100 g and 72 g/100 g), lipids (8 g/100 g and 9 g/100 g), and protein (7 g/100 g and 3 g/100 g). The lipophilic extract of both fractions had similar amounts of β-sitosterol (30 mg/g), differing in the amount of long-chain aliphatic alcohols, namely nonacosan-10-ol (8 mg/g and 51 mg/g for finer and coarser fractions, respectively) and secondary/secondary alkanediols (18 mg/g and 185 mg/g), known as emulsifier compounds. The composition of pine nut skin fractions indicated their potential in affecting the cholesterol absorption in the intestinal lumen. The lipophilic extract from the finer fraction showed to decrease cholesterol micellar solubilization, and the polysaccharides and lignin had bile salt sequestration properties, rendering this byproduct an hypolipidemic potential. The coarser fraction showed potential as a substitute of egg yolk (3.4 g/100 g dry weight) in a mayonnaise formulation (49 g/100 g oil in water emulsion), an emulsifying capacity ascribed to the dietary fiber content and to its lipophilic fraction. From pine nut skin it is possible to obtain low-cost food ingredients with relevance as emulsifiers and potential hypocholesterolemic activity.