International Journal of Material Science Innovations (IJMSI) 2(3): 47-51, 2014 ISSN 2289-4063 Academic Research Online Publisher Research Article The Extraction of Lactic acid from Maize (Zea may) Mahmud Hauwau a Department of Chemical Engineering Technology, School of Engineering Technology, Auchi Polytechnic, P.M.B. 13, Auchi, Nigeria Correspondence Tel.: +2348029320114 A b s t r a c t Keywords: Lactic acid, Maize, Extraction, characterization. The lactic acid was produced from maize by fermentation process using calcium carbonate, calcium hydroxide and sulphuric acid as reagents. Three different samples were produced by varying the concentration of the reagent, these results to samples A, B and C. The molarity varies from 0.034, 0.0173 and 0.0084 respectively. The percentage lactic acid content before concentrating the samples by evaporation increased to 4.80, 2.20 and 1.50 for sample A, B and C, respectively. Accepted:05 June2014 Academic Research Online Publisher. All rights reserved. 1. Introduction Acids are chemical compounds containing hydrogen atom(s) that can be replaced by metal atom to produce a salt. They have sour taste and turn litmus red when dissolved in water, they dissociate into ions, strong acid dissociate completely in water while weak acid do not. Weak acids are mostly organic acids [1]. Lactic acid is a colorless liquid organic acid which is miscible with water or ethanol. It is the fermentation product of lactose which is the primary acid constituent of naturally soured milk hence it s name. Lactic acid is also a normal constituent in the blood and muscle tissue of animal [2]. Lactic acid is used in food and beverages industries as flavouring and preservative, in dyeing and textile printing, in plastic manufacturing industry and in pharmaceuticals. It is also used as raw material or catalyst in many chemical processes. Lactic acid has been identified in yeast fermentation and is a major component of corn steep liquor, by product such as beer pickles, cheese and buttermilk. Lactic acid can be manufactured either by product such as beer pickles, cheese and buttermilk.
Lactic acid can be manufactured either by fermentation or by synthesis. Fermentation of any nontoxic carbohydrate product, by-product or waste may be used as stating material, while in synthetic process the basic reaction is the conversion of lactonitrile into lactic acid [2]. The Aim and objective of this research is to produce edible grade lactic acid using maize {Zea may). Maize is use as the raw material because it is readily available and cheap in Nigeria. 2. 2. Materials and Methods 2.1. Material The major raw material for the production of lactic acid from maize is the maize itself, all other reagents are of analytical grade. 1kg of dried maize seeds was obtained from Igbe market, Auchi, Nigeria. The collected maize seeds were threshed using a tray to remove chaff and other foreign material. 2.2. Preparation of Maize Maize was submerge in water to allow it soften and swell for the period of three days. The maize was washed and wet milled one and then half (1/2) litres of water was added, to make a slurry. 500ml of the slurry was measured using a measuring cylinder into a fermenter and 10ml of lactobacillus was added. This was covered properly and allowed to ferment for four days. The sample is then labeled A. 1.5M calcium carbonate was added in excess in order to neutralize the lactic acid created by the fermentation, this results in a mixture containing calcium lactate and carbon oxide. The mixture was first alkalized with 10ml of 1.5M calcium hydroxide and boiled magnesium precipitate alongside chaff and these were filtered off. The filtrate was then regenerated with 20ml of 1.5M sulphuric acid. Precipitate of calcium sulphate was observed and was filtered off. A light colored filtrate was collected for further analysis and refining process. Another 500ml of corn slurry each were measured in two other fermenters labeled B and C same procedure was carried out but using 1.0M and 0.5M of reagents respectively 200ml each of sample A B and C were measured and concentrated by evaporation resulting to samples A B and C respectively [3]. 2.3. Test for Lactic Acid 10ml of sample A was measured and 1ml of concentrated sulphuric acid was added, this convert the lactic acid to acetaldehyde. 3 drops of p-hydroxyl diphenyl was added to the acetaldehyde and warmed; a violet color confirms the presence of lactic acid. Similar test was conducted for samples B and C [3]. 48 P a g e
3. Results and discussion Based on the result obtained, lactic acid can be produced using maize as raw material. From the result in table 1 before concentrating the sample, the percentage content of lactic acid were 3.40, 1.73 and 0.84 for sample A, B and C respectively. This clearly shows that the higher the molar concentration of reagents used the higher concentration of lactic acid. Concentration of reagents greatly influences the conversion of maize to lactic acid [4]. The yield obtained is low compare to 10% from literature [4]. Table 1: Determination of % lactic acid contents before concentrating the simples S/N Sample code Volume of NaOH Conversion factor Amount of sample Lactic acid (g) %. Lactic acid used (ml) used in (ml) 1. A 40 0.009 10 0.034 3.40 2. B 15 0.009 10 0.0173 1.73 3. C 10 0.009 10 0.0084 0.83 Table 2 shows the percentage lactic acid content after concentrating the sample by evaporation: 4.80, 2.20 and 1.50 for samples A, B, and C respectively. The yield obtained is low compare to 20% from literature [4]. Generally, the low yield obtained can be attributed to error or the incomplete conversion of maize to lactic acid on laboratory scale, and the high boiling point of lactic acid during the fermentation process. Table 2: Determination of % lactic acid contents after concentrating the simple by evaporation S/N Sample code Volume of NaOH Conversion factor Amount of sample Lactic acid (g) %. Lactic acid used (ml) used in (ml) 1. A 1 50.60 0.009 10 0.048 4.80 2. B 1 24.00 0.009 10 0.022 2.20 3. C 1 19.50 0.009 10 0.015 1.50 In this refining process, steam distillation method cannot be employed because the production of lactic acid is on laboratory scale, the high boiling point of lactic acid will result in the formation of non-volatile polyester thereby reducing the yield to a fraction of the original [5,6]. Liquid-liquid extraction method is ruled out because it is a continuous process that is usually employed on a commercial scale [7,8]. The use of ion exchange route has been attempted, but has yielded no positive result; this is because of the minute quality of the lactic acid in the samples. 49 P a g e
The problem of lactic acid production form maize does not only lie in the fermentation process but mainly in the recovery process [9, 10] as it is almost impractical to isolate lactic acid on laboratory scale. Therefore test was carried out to confirm the presence of lactic acid in the sample mixture. The test carried out to confirm lactic acid presence involved the use of concentrated sulphuric acid on the sample mixture and addition of p-hydroxyl diphenyl which on warning gave a violet color that confirmed the presence of lactic acid in the mixture. 4. Conclusions From this result obtained in this research, it can be concluded within the limit of the findings that maize can be fermented to produce lactic acid. From the analysis carried out, it can be concluded that maize seed contains lactic acid in quantities that can supplement that produced from milk and other sources. References [1] Kent N. L. Chemical analysis of Food 2 nd Edition Elsevier Applied Science Publisher Limited, England, 1982; 72-78. [2] Kirk Othmer Encyclopedia OF Chemical Engineering Technology, 2 nd Edition (12). McGraw Hill Book Company, New York, 1967. [3] Yaraslastsev A, Kreshkor A. P. Course of Analytical Chemistry (2), MIR Publisher, Moscow, 1977; 89-96. [4] Bernard A. Ferda M. Biochemical Engineering and Biotechnology Hand Book 2 nd Edition, Macmillan Publishers Ltd, Nigeria, 1991; 243-237. [5] Department of Food Technology Practical Manual on Food Technology, Nutrition and Dietetic for school and industry, 2 nd Edition. National Science and Technology Forum, Kaduna olytechnic, Kaduna Nigeria, 2004; 56-62. [6] Felix E. And Ronald J. Physical Properties of Food (2), Elsevier Applied n ience Publisher Limited, England, 1987; 98-122. [7] pigcott J. R. Analysis of Food 2 nd Edition, Elsevier Applied Science Limited, England, 1988;167-234. [8] Okereke P The use of Cashew Tree for the control of Stored Cowpea Beetle, journal of Agricultural Science, Cambridge, UK, 1999; 112-118. [9] Parker S. P. McGraw-Hill Dictionary of Science and Technology Terms, 4 th Edition McGraw-Hill Book Company, USA, 1993. 50 P a g e
[10] Unguru O. O An introduction to Agricultural Science for tropical Areas 2nd Edition Thomas Nelson and Sons Limited, Nigeria, 1981; 89-94. 51 P a g e