Statistical optimization of aqueous extraction of pectin from waste durian rinds Statistical optimization of aqueous extraction of pectin from waste durian rinds Statistical optimization of aqueous extraction of pectin from waste durian rinds
G Model ARTICLE IN PRESS BIOMAC 4698 1–7 International Journal of Biological Macromolecules xxx (2014) xxx–xxx Contents lists available at ScienceDirect International Journal of Biological Macromolecules journal homepage: www.elsevier.com/locate/ijbiomac Statistical optimization of aqueous extraction of pectin from waste durian rinds Q1 J Prakash Maran ∗ Department of Food Technology, Kongu Engineering College, Perundurai, Erode 638052, TamilNadu, India 18 a r t i c l e i n f o a b s t r a c t 10 11 12 Article history: Received 25 August 2014 Received in revised form 16 October 2014 Accepted 22 October 2014 Available online xxx 13 17 Keywords: Pectin Durian rind Extraction 19 Introduction 14 15 16 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 The objectives of this present study was to investigate and optimize the aqueous extraction conditions such as solid-liquid (SL) ratio (1:5–1:15 g/ml), pH (2–3), extraction time (20–60 min) and extraction temperature (75–95 ◦ C) on maximum extraction of pectin from durian rinds using four factors, three levels Box-Behnken response design The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and analyzed by analysis of variance (ANOVA) The optimum extraction condition was found to be as follows: SL ratio of 1:10 g/ml, pH of 2.8, extraction time of 43 and extraction temperature of 86 ◦ C respectively Under the optimal conditions, the experimental pectin yield (9.1%) was well correlated with predicted yield (9.3%) © 2014 Published by Elsevier B.V Pectin is a family of complex heteropolysaccharides consisting of a backbone of ␣-(1 → 4) galacturonic acid residues which are partially esterified with methyl alcohol or acetic acid at the carboxylic acid As a structural component of plant cell wall, it is extensively distributed in the primary cell wall and middle lamella of all plant tissues [1] Pectin is also used as a gelling and stabilizing agent in the food and cosmetic industries and has multiple positive effects on human health including lowering cholesterol and serum glucose levels, reducing cancer [2], and stimulating the immune response [3] Pectin is also used in the production of a variety of specialty products including edible and biodegradable films, adhesives, paper substitutes, foams and plasticizers, surface modifiers for medical devices, materials for biomedical implantation, and for drug delivery [4] The world market demand for pectin is in excess of 30,000 tons annually and is growing by about 4–5% per annum [5] Durian (Durio zibethinus) is ovoid or ovoid-oblong to nearly round shaped fruit and one of the most highly valued and desired fruits among various fruits due to its distinct flavour and unique taste The rind which usually weighs more than half of the total fruit weight is green to yellowish brown, thick and semi-woody with sharply pointed pyramidal thorns [6] During the season of durian, the amounts of rind that disposed as waste could lead to ∗ Tel.: +91 4294 226606; fax: +91 4294 220087 E-mail address: prakashmaran@gmail.com environmental problems But these rinds are rich in polysaccharide materials Therefore, conversion of durian rinds into valuable compounds not only reduces the waste disposal but also provides an economically viable alternative resource for polysaccharide production Extraction is a low cost technology to obtain molecules to be used as food additives or nutraceutical products Extraction of polysaccharide from permeable waste solid plant materials using solvents constitutes an important step in the manufacture of value added by-products From the literature analysis, many factors such as extraction time, extraction temperature, solvent to solid ratio, pH, mass of plant materials, solvent composition and solvent type, may significantly influence the extraction efficacy of diverse natural products [7–9] In this case, both the optimization of the process and investigation of their combined effects were lengthy and tedious Response surface methodology (RSM) was proved to be an effective way for the above-mentioned purpose, which was a collection of statistical and mathematical techniques, which has been successfully used for developing, improving, and optimizing processes [10] From the literature analysis, it was found that, there are no systematic studies on aqueous extraction of pectin from waste durian rinds using RSM Hence, an attempt was made for the first time to investigate and optimize aqueous extraction of pectin from waste durian rinds using three levels, four factors (solid-liquid ratio, pH, extraction time and extraction temperature) Box-Behnken response surface design (BBD) combined with numerical optimization method Box-Behnken is a spherical, revolving response surface methodology (RSM) design that consists of a central point and the middle points of the edges of the cube circumscribed on http://dx.doi.org/10.1016/j.ijbiomac.2014.10.050 0141-8130/© 2014 Published by Elsevier B.V Please cite this article in press as: J.P Maran, Int J Biol Macromol (2014), http://dx.doi.org/10.1016/j.ijbiomac.2014.10.050 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 G Model ARTICLE IN PRESS BIOMAC 4698 1–7 J.P Maran / International Journal of Biological Macromolecules xxx (2014) xxx–xxx 74 the sphere It consists of three interlocking 22 factorial designs with points lying on the surface of a sphere surrounding the center of the design [11] 75 Materials and methods 72 73 76 k 2.1 Raw materials and reagents j=1 88 89 2.2 Extraction of pectin 78 79 80 81 82 83 84 85 86 87 ˇjj Xj2 + ˇj Xj + 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 The dried durian rind powder was weighed and placed into a 250 ml Erlenmeyer flask and were extracted with distilled water The pH of the distilled water was adjusted with the help of hydrochloric acid The extraction was performed under different extraction temperature (75–95 ◦ C) with diverse pH values (2–3) and solid-liquid ratios (5–15 g/ml) at various extractions times (20–60 min) Erlenmeyer flask was covered with a plastic wrap during the experiments to prevent evaporation of solvent After extraction for a selected time (Table 1), the mixtures were filtered through cheese cloth and allowed to cool to room temperature (30 ◦ C) Ethanol (95%) was added to the filtrate in a 2:1 ratio and stored at ◦ C for 24 h The polysaccharides containing pectin were removed by centrifugation (10,000 rpm, 10 min) and then washed twice with ethanol in order to remove the mono and disaccharide After one hour, the pectin was separated as a precipitate by filtration The wet pectin was dried in a hot air oven at 55 ◦ C until a constant weight was achieved The percentage of pectin yield (PY) was calculated from the following equation [12]: PY = Massofextractedpectin Massofdriedrindpowder × 100 113 114 2.3 Experimental design 110 111 112 123 In this study, Box-Behnken response surface design (BBD) with four factors with three levels was chosen to investigate and optimize the influence of process variables such as SL ratio (5–15 g/ml), pH (2–3), extraction time (20–60 min) extraction temperature (75 –95 ◦ C) on the maximum pectin extraction yield from durian rinds The experimental design consists of 29 experiments with five central points (used to approximate experimental error) were carried out (Table 1) and total numbers of experiments (N) were calculated from the following equation [13] 124 N = 2K (K − 1) + C0 115 116 117 118 119 120 121 122 125 126 (2) where, K is number of factors and C0 is the number of central point 128 129 130 (3) 131