Application of Taguchi Method in the Enzymatic Modification of Menhaden Oil to Incorporate Capric Acid

Abstract

Structured lipids (SL) were produced using menhaden oil and capric acid or ethyl caprate as the substrate. Enzymatic reaction conditions were optimized using the Taguchi method L9 orthogonal array with three substrate molar ratio levels of capric acid or ethyl caprate to menhaden oil (1:1, 2:1, and 3:1), three enzyme load levels (5, 10, and 15% [w/w]), three temperature levels (40, 50, and 60 C), and three reaction times (12, 24, 36 hours). Recombinant lipase from Candida antarctica, Lipozyme ® 435, and sn-1,3 specific Rhizomucor miehei lipase, Lipozyme ® RM IM (Novozymes North America, Inc., Franklinton, NC, USA), were used as biocatalysts in both acidolysis and interesterification reactions. Total and sn-2 fatty acid compositions, triacylglycerol (TAG) molecular species, thermal behavior, and oxidative stability were compared. Optimal conditions for all reactions were 3:1 substrate molar ratio, 10% [w/w] enzyme load, 60 C, and 16 hours reaction time. Reactions with ethyl caprate incorporated significantly more C10:0, at 30.76 AE 1.15 and 28.63 AE 2.37 mol% versus 19.50 AE 1.06 and 9.81 AE 1.51 mol%, respectively, for both Lipozyme ® 435 and Lipozyme ® RM IM, respectively. Reactions with ethyl caprate as substrate and Lipozyme ® 435 as biocatalyst produced more of the desired medium-long-medium (MLM)type TAGs with polyunsaturated fatty acids (PUFA) at sn-2 and C10:0 at sn-1,3 positions. Keywords Structured lipids Á Menhaden oil Á Taguchi method Á TAG molecular species Á Lipozyme ® 435 Á Capric acid J Am Oil Chem Soc (2018) 95: 299-311.Fig. 4 TOTOX and OSI values for menhaden and large-scale SL (reaction conditions of 3:1 ethyl caprate/menhaden oil substrate molar ratio, 10% Lipozyme ® 435, 60 C, and 16 hours).TOTOX value = 2(PV) + pAV, where PV = peroxide value, pAV = p-Anisidine value 310 J Am Oil Chem Soc J Am Oil Chem Soc (2018) 95: 299-311

Enzymatic Modification of Menhaden Oil to Incorporate Caprylic and/or Stearic Acid

“…Substrate molar ratios were selected based on previous studies (Jennings and Akoh, ; Yamaguchi et al, ). Lipase, Lipozyme® 435 or Lipozyme® RM IM, was added at 10% total weight of the substrates, and was based on a previous study (Willett and Akoh, ). Reactions were conducted in a 250 rpm shaking water bath at 65 or 75 °C for 8:0 or 18:0 acyl donor substrates, respectively.…”

“…Previous studies have modified menhaden oil; however, the TAG molecular species was not determined for the products (Jennings and Akoh, , ; Xu et al, ). A previous study in our lab produced an MLM‐type SL of menhaden oil and capric acid using ethyl caprate as the acyl donor; however, the melting point was less than 25 °C (Willett and Akoh, ). Our current interest was to produce MLM‐type SL with a higher melting point (25–35 °C) for use in a wider range of applications.…”

Solvent‐Free Enzymatic Synthesis of 1‐o‐Galloylglycerol Optimized by the Taguchi Method

“…Tukey's honest significant difference test (Tukey HSD) and the LSD test were used to determine the differences that occurred when varying each reaction parameter and the level of significance ( P < 0.05). The S/N ratio is a measure of the robustness that can be used to detect the control factor settings for a minimum impact of noise on a response (Willett and Akoh, ). The larger the S/N is, the higher the yield, as shown in Eq.…”

“…Candida antarctica lipase B (CALB) has a funnel‐like active center with a very short lid, which is similar to esterases, and is inclined to adapt to more voluminous acids such as benzoic acid and its derivatives (Tamayo et al, ). Lipozyme® 435 is a commercially available food‐grade immobilized form of CALB (Willett and Akoh, ). It has high thermostability and is capable of catalyzing reaction in a solvent or in solvent‐free media (Willett and Akoh, ).…”

“…Lipozyme® 435 is a commercially available food‐grade immobilized form of CALB (Willett and Akoh, ). It has high thermostability and is capable of catalyzing reaction in a solvent or in solvent‐free media (Willett and Akoh, ). Based on its properties, Lipozyme® 435 appears to be a good choice for enzymatically synthesizing GG for use in food products.…”