Enzymatic hydrolysis of palm cellulose to yield nanocrystals with potential roles in lipid and cholesterol digestion and absorption

Abstract

Limited research has been conducted to understand the influence of cellulose nanocrystals (CNCs) on lipid and cholesterol digestion and absorption. This study aimed to explore and understand the ability of CNCs to modulate these processes. CNCs were obtained from palm-pressed fiber (PPF) via a green enzymatic hydrolysis method, a more environmentally friendly alternative to the traditional, acid hydrolysis. Enzymatic hydrolysis was performed using the endo-β-D-glucanase derived from Aspergillus sp. The effect of the enzyme concentration (250–1000 U/g) and reaction times (12–72 h) on CNC particle size, morphology, yield and suspension stability were studied. Enzymatic hydrolysis at a concentration 500 U/g and 72 h of incubation successfully produced needle-shaped, shortened, and non-entangled CNCs with an average diameter of 22.76 ± 5.52 nm, length of 342.55 ± 148.69 nm, an aspect ratio of ~ 15, and a crystallinity of 61.45%. Interestingly, the water (22.28 ± 0.85 g/g) and oil (15.08 ± 0.62 g/g) holding capacities of CNCs were four times higher than raw PPF (5.31 ± 0.53 g/g; 3.52 ± 0.32 g/g). The results showed increasing CNCs concentrations decreased lipase activity mobilization, increased cholesterol adsorption capability and retarded bile acid diffusion. 1% of CNCs alone inhibited 54.93% of lipase activity. 1 g of CNCs adsorbed 54.19 ± 10.70 mg of cholesterol and demonstrated a greater bile acid retardation effect than microcrystal cellulose (CNCs: 39.3 ± 10.10%: MCC: 27.05 ± 6.72%). The entrapment of lipase and bile acid by CNCs could affect lipid and cholesterol digestion, potentially benefiting digestion health applications. Furthermore, the presence of CNCs could potentially alleviate hypercholesteremia by adsorbing cholesterol and reducing bile acid diffusion. The results revealed the effectiveness of CNCs extraction from PPF through enzymatic hydrolysis and suggest that CNCs may have health benefits as a functional ingredient for developing of fat- and cholesterol-rich foods with health-promoting properties.