Natural Product Radiance, Vol. 7(2), 2008, pp.127-132 Research Paper Ethanol recovery from solid state fermented apple pomace and evaluation of physico-chemical characteristics of the residue V K Joshi*and A Devrajan Department of Postharvest Technology Dr Y S Parmar University of Horticulture and Forestry Nauni, Solan-173 230, Himachal Pradesh, India *Correspondent author, E-mail: [email protected]; Phone: +91-01792-252410 Received 23 April 2007; Accepted 29 November 2007 handled properly. Thus, there is a strong Abstract In view of the growing demand of ethanol the identification of resources and development need to devise techniques to utilize apple of economical methods for its extraction are very essential. Fermented apple pomace has been pomace in an economical and effective identified as a rich source of ethanol especially for the Himalayan region where apple is grown at way to avoid the environmental pollution large scale. There are various methods of alcohol recovery from solid state fermented apple and to obtain value-added products from pomace (hot water extraction followed by distillation, vacuum distillation, hydraulic pressure and waste materials3-5. direct steam distillation) hence, present study was carried out to standardize an efficient and economical method. The physico-chemical characteristics of dried apple pomace residue after the Use of apple pomace has been recovery of ethanol by different methods were also evaluated for knowing loss of nutrients during made through fermentation into several extraction of ethanol. For present study two types of solid state fermented (SSF) apple pomace, products including citric acid, ethanol, obtained by two treatments (one by Saccharomyces cerevisiae and other by Candida utilis pigment, mushroom substrate, single cell and Kloeckera spp. as sequential interactive co-cultures) were used. Out of different methods of protein, etc4-8. The most promising alcohol recovery tried, steam distillation method gave the highest separation efficiency while hydraulic pressing gave the lowest separation efficiency. Evaluation of some of the physico-chemical method for complete utilization of apple characteristics of dried apple pomace after recovery of ethanol by different methods indicated that pomace may be through solid state steam distillation resulted in minimum nutritional loss, viz. crude and soluble proteins, reducing fermentation with yeasts, separating out and total sugars. The maximum nutritional loss took place in hydraulic pressing, wherein the base ethanol and using the left-over protein of distillate was not added back to the pomace, prior to drying. Steam distillation method of rich material after drying as an animal ethanol recovery from fermented apple pomace was the best since it gave the dried pomace with minimum loss of nutrients. feed. Concomitant production of ethanol and animal feed from apple pomace has Keywords: Ethanol recovery, Apple pomace, Malus pumila, Physico-chemical characteristics, 9, 10 Steam distillation. also been reported . Among the strategies employed to recover products IPC code; Int. cl.8— C12F 3/08, C12S 3/00, C12S 3/14 from fermented solids are the percolation techniques, multiple contact counter Introduction products of juice extraction and is current leaching, supercritical fluid Apple (Malus pumila Mill. generated in large quantities which are extraction, hydraulic pressing and pulsed syn. M. domestica Borkh.) is the oldest difficult to handle especially in hilly areas plug flow extraction11. Although ethanol fruit known to man and is grown thus, creates environmental pollution. It separation has been reported from pulpy extensively throughout the temperate is a rich source of several nutrients hence, fermented tapioca12, till now only vacuum zones of the world. Several processed throwing it into the river is not distillation method has been applied to products like juice concentrate, jam, jelly, appreciated. Being a rich source of several separate out ethanol from fermented apple squash, preserve, wine, cider, vermouth, nutrients and organic matter it is highly pomace. In the present paper results of etc. are made from apple1, 2. At the same biodegradable in nature which affects various methods adopted for extracting time, it also results in the generation of ecosystem and creates foul smell around ethanol from solid state fermented waste3. Apple pomace is one of the by- the fruit processing industries, if not apple pomace have been communicated. Vol 7(2) March-April 2008 127 Research Paper Materials and Methods arrangement is shown in Fig. 2. as an indicator and was expressed as per Solid state fermentation: (iii) Steam distillation: Fermented cent malic acid15. The total and reducing Sequential co-culture of apple pomace apple pomace (1.5 kg) was sugars were measured by Lane and Eynon’s was carried out in solid state transferred to 5L conical flask and the volumetric method16. Crude protein was fermentation, using five yeasts, same quantity of water was added. The estimated by micro-kjeldahl method16. Saccharomyces cerevisiae, mouth of the flask was fitted with a Soluble proteins were measured by using Kloeckera, Schizosachharomyces cork having a steam inlet going up to the method of Lowry et al (1951)17. In pombe, Candida utilis and Torula the bottom of the flask (Fig. 3). Steam the estimation, 500 mg of dried and utilis. The fermentations were carried out was generated in an autoclave up to ground sample were taken and the soluble in 5 litre conical flasks with 3 kg of 25lb and thereafter, the steam was proteins were extracted in 19.5 ml of reconstituted apple pomace. Conditions released into the flask. From the top phosphate buffer (pH 7.5). The sediments of fermentations were the same as outlet of flask, steam was collected were removed by centrifuging at 4500 rpm reported earlier13. The best two and condensed. and estimation was made as per the treatments, viz. SSF fermented first by (iv) Vacuum distillation: Hot water method described. Saccharomyces cerevisiae and second (175 ml) at 50oC was added to the by Candida utilis followed by fermented apple pomace (175g). The Results and Discussion Kloeckera spp. were selected on the material was allowed to stand for 30 The mass flow and the separation basis of high ethanol and crude protein min and was transferred to vacuum of ethanol from fermented apple pomace content, respectively. distillation flask which was kept in a by four different methods are shown in Ethanol recovery: Ethanol in water bath (Fig. 4). The temperature Table1. Differences in the initial ethanol o the fermented apple pomace was extracted was maintained constantly at 70 C. content exhibited by the results reflect the by four different methods described Drying of apple pomace differences in the two treatments at the below: residue: The fermented apple pomace start of fermentation. It is also evident that (i) Hydraulic pressing: Fermented apple was dried in a mechanical dehydrator at complete alcohol in the fermented apple o pomace (1.5 kg) was transferred to 60 + 1 C for 8h (Fig. 5) and thereafter, pomace is not removed in the first press, 5L conical flask. Hot water (750ml) ground into powder. It was packed in as shown by the alcohol levels in the first was added at 50oC and the flask along polythene bags. The dried apple pomace and second press. It has also been reported with contents was allowed to stand for was analysed for different parameters, viz. earlier that leaching of the product from 30 min, followed by pressing. To the proteins (crude and soluble) and total fermented solids in a single contact step second press, the same quantity of sugars. would not be 100% effective as the dry water was added, followed by pressing Physico-chemical analysis of solids absorb aqueous solvent two times (Fig. 1). The pooled extract of both dried apple pomace: Various physico- the weight of the solids in case of wheat the extractions were collected and 1/ chemical characteristics of apple pomace bran18. Further, the final ethyl alcohol 3rd of the initial content of material were analysed. Ethyl alcohol was contents in the distillates were according 14 was distilled (1L). determined by colourimetric method and to that present in the fermented apple o (ii) Direct distillation: The fermented TSS was measured in Brix using Erma pomace after solid state fermentation apple pomace (1.5 kg) was hand refractometer. The readings were (SSF). transferred to 5L conical flask and the corrected by applying the correction factor The average ethanol separation 15 water and fermented apple pomace for temperature variation . Titratable efficiency of four different methods varied ratio was kept at 1:1. The flask was acidity was determined by titrating a from 73.16 to 99.45 per cent. The highest directly kept on the heater, followed known aliquot of the sample (solid ethanol separation efficiency was shown by distillation and 1/3rd of the total materials were diluted to 10 times) against by steam distillation and the lowest by hot volume was distilled (1L). The N/10 NaOH solution using phenophthalein water extraction followed by pressing in 128 Natural Product Radiance Research Paper 1 2 3 form of vapours due to uniformally high temperature. There is no report on the separation efficiency of ethanol from apple pomace using different methods except separation of ethanol by vacuum distillation by Hang et al (1982)6 whose results also confirm these findings. The fermented apple pomace of different treatments after removal of ethanol by different methods as discussed earlier, was dried separately and analyzed for 4 5 different physico-chemical characteristics (Table 2). It is clear from the results that extraction of ethanol by different methods did not have any significant effect on moisture content of dried apple pomace. Since similar time, temperature and drying method were employed for all the four treatments it might be the reason for the non- Fig. 1-5: 1. Ethanol containing liquid being separated by hydraulic pressing of fermented apple pomace; significant differences 2.