D-isoascorbyl palmitate: lipase-catalyzed synthesis, structural characterization and process optimization using response surface methodology

Abstract

Background: Isoascorbic acid is a stereoisomer of L-ascorbic acid, and widely used as a food antioxidant. However, its highly hydrophilic behavior prevents its application in cosmetics or fats and oils-based foods. To overcome this problem, D-isoascorbyl palmitate was synthesized in the present study for improving the isoascorbic acid's oil solubility with an immobilized lipase in organic media. The structural information of synthesized product was clarified using LC-ESI-MS, FT-IR, 1 H and 13 C NMR analysis, and process parameters for high yield of D-isoascorbyl palmitate were optimized by using One-factor-at-a-time experiments and response surface methodology (RSM). Results: The synthesized product had the purity of 95% and its structural characteristics were confirmed as isoascorbyl palmitate by LC-ESI-MS, FT-IR,

Evaluation of reaction parameters and kinetic modelling for Novozym 435 catalysed synthesis of isoamyl butyrate

“…Hence, molecular sieves were found to be beneficial and efficient not only towards higher conversion but also prevention of damage to catalyst by adsorbing excess water around it . Similar trends are reported for the conversion of D‐isoascorbyl palmitate where the addition of 4 Å molecular sieves at a temperature 50 °C improved the conversion to more than 85% in 24 h . Thus, optimisation studies and the impact of reaction parameters such as temperature, mole ratio of substrates, catalyst loading, etc.…”

“…This is attributed to the fact that higher enzyme loading could aggregate and inhibit the exposure of active enzyme sites affecting the reaction process. In addition, the enzyme particles are also exposed to high substrate concentration on their external surfaces, inhibiting the mass transfer of substrate inside the enzyme particles . Hence, effective interaction of enzyme and substrate is hampered along with inefficient exposure of active sites since the rate and number of collisions between reactants and catalyst reduce with excess concentration of lipase …”

High-yield synthesis of bioactive ethyl cinnamate by enzymatic esterification of cinnamic acid

“…The optimal water activity represented the most appropriate water condition from the balance between these conflicts, whereas the lower water activities provided insufficient water for the buildup of the essential water shell for enzyme, and the higher water activities implied excessive water and thereby the increasing competition of water for the acyl-enzyme intermediate (Wehtje & Adlercreutz, 1997). In addition, an over-high water activity probably increased the thickness of water layer around the enzyme molecule, which would cause diffusion-limited problems of substrates entry into or products release from the lipase molecules (Sun et al, 2013). Therefore, the strong competing hydrolysis and the diffusion-limited problems could explain the much lower yield at higher water activities in Fig.…”

“…Temperature not only affects the stability and the activity of the enzyme but also the reaction equilibrium, as well as the properties of reaction media such as viscosity (Li, Chen, & Tan, 2011;Sun et al, 2013). Fig.…”

Evaluation of Pulp Browning in Minimally Processed 'Royal Gala' Apple Treated With Erythorbic Acid

“…The use of EA as an antibrowning agent was evaluated in MP 'Ágata' potatoes (Pineli et al, 2005), canned apple and beer (Andersen 1999). In addition, EA is considered a safe food antioxidant in the European Union and the US, when used according to its legislation (Sun et al, 2013, EFSA 2016. Despite the proven antioxidant properties, there are few reports in the literature evaluating the use of EA as a darkening inhibitor in MP apples.…”