New Technologies for Value Added Products from Coconut Residue

Abstract

This paper deals with the technologies developed in the field of coconut research at CFTRI in the last three decades including process for desiccated coconut, technology development for the production of spray dried coconut milk powder, wet processing of coconut, vinegar generation from coconut water, virgin coconut oil, tender coconut based beverage, coconut spread etc. CFTRI is in forefront in developing technologies for coconut-based products. Some of these technologies have been successfully transferred and most of the produce is being exported. Our current research efforts are focused on production of low fat dietary fiber from coconut residue after the milk extraction, concentration of coconut water by membrane processing, preservation of coconut water by emerging technologies will also be discussed. Introduction The word ‘Coco’ is derived from Spanish word ‘Macoco’, which refers to three holes on coconut that resemble the face of an ape. The coconut is mainly produced in southern states of India such as Kerla, Karnataka, Andhra Pradesh, Maharashtra etc. The tree of coconut is called as kalptaru, because all the parts of it are useful in one form or the other. Specially, the kernel of matured coconut is most valuable and is used for edible purpose as such or in dehydrated form. The dried kernel known as ‘copra’ and is the richest source of vegetable oil and the coconut oil cake is a valuable feed for livestock and a source of protein. The coconut shell is mainly used as a fuel, for making decorative items, shell powder, shell charcoal and biodegradable containers etc. The husk yields fiber, which is converted into coir and its products. The coir pith obtained during the defibring process is used as an ideal soil conditioner. The coconut water is one of the valuable by-products of the coconut processing industries, which can be subjected to fermentation to produce vinegar. The economy of the coconut-processing sector is mainly dependent on the copra and coconut oil, and on desiccated coconut to a less extent. About 60% of the total coconut production is used for edible purpose, 3.5% as tender coconut, 35% as milling copra for oil extraction and balance is processed into products like desiccated coconut. Coconut oil contributes about 6% of the total edible oil demand. In order to develop the diversified products from coconut and to improve the economy of this sector Coconut Development Board, India has taken a welcome step in sponsoring research projects at different institutions for the development of technologies in this regard. CSIR-CFTRI is in forefront in developing technologies pertaining to diversified products from coconut. Coconut Related Technologies Developed at CFTRI A. Desiccated Coconut Powder The process includes removal of shell and paring, disintegration of white endosperm, final drying in the drier and then packaging. On an average 1000 nuts give 110 kg of DCP. By-Products of Palm Trees and Their Applications Materials Research Forum LLC Materials Research Proceedings 11 (2019) 295-301 doi: https://doi.org/10.21741/9781644900178-25 296 Several units located in India produce about 15,000 tons annually. All are in the small-scale sector with capacities ranging from 0.5-1.0 ton per day. DCP is mainly used in biscuits, sweets, bakery products and other food preparations. B. Spray Dried Coconut Milk Powder Coconut milk is a product of the region of tropical climate and is in great demand in the international culinary. It is a white milky product extracted from the endosperm of coconut and constitutes into an emulsion stabilized by proteins and probably, by some ions found in oil-water interface. Coconut milk is an important dietary in coconut producing countries. It is valued mainly for its characteristic nutty flavour and also for its nutritional values. It is an ingredient for many fish, shellfish, meat, poultry, vegetable dishes, confectioneries, sweets, serbhats, beverages and other type of preparations. Under ambient conditions coconut milk shows poor stability and the emulsion separates into two distinct phases: a heavy aqueous phase and a lighter creamy phase. Coconut milk extracted from freshly grated coconut meat undergoes very fast progressive deterioration at room temperature due to its high content of fat, moisture and other organic components, which quickly deteriorate upon exposure to microorganism, light, oxygen and high temperature. Based on our previous experience and published reports, it was opined that dehydration is the best feasible method for the preservation of coconut milk. Dehydrated coconut milk powder which retains the natural flavour and texture of coconut milk, yet has good keeping quality, would lead to greater convenience and increased consumption. Individual and institutional user would be relieved from the task of extracting milk. Further, it offers additional advantages such as less storage space and extended shelf life. Very little information is available in the literature regarding the dehydration of whole coconut milk, though lot of information is available on dehydration of skim coconut milk powder. And out of available information most of it either remained proprietary or available in languages other than English or in the form of patents. The only report available is work of Hassan [1]. The process for the production of whole coconut milk powder involves various unit operations such as size reduction, extraction of milk, stabilization of emulsion, homogenization and spray drying. The coconut milk contains large amount of fat, which poses difficulty in achieving its stabilization during spray drying. A process was developed to stabilize coconut milk, which enables spray drying [2]. Recently, technology for the production of whole coconut milk powder has been transferred to an Indian industry. The process was developed for detachment of coconut kernel from shell [3]. The white endosperm after removal of shell and paring was passed through rotary wedge cutter having a sieve plate (3 mm. hole) through which shredded meat is forced out. This moist coconut grating was expressed in a screw press to extract coconut milk. Coconut milk, thus obtained, was homogenised in two stage of high and low pressures, respectively, over a period of 30 minutes. Then coconut milk was formulated by addition of certain ingredients and chemicals etc. This formulated coconut milk was pasteurised at 60-70C for 5 minutes and homogenised again. Finally, the milk was spray dried at temperature 100-150C at a feed flow rate of 120 ml/minute and packed [4]. The flow sheet of the process is given in Figure 1. Apart from the processing technology, quality and yield of the extract (coconut milk) is affected by several factors such as varietal differences, coconut maturity, meat particle size, processing temperature and extraction pressure. It is observed that maturity of coconut has considerable effect on the yield of coconut milk. It was observed that the yield was less if the coconuts were over or under matured. When the meat particle size was less it was observed that By-Products of Palm Trees and Their Applications Materials Research Forum LLC Materials Research Proceedings 11 (2019) 295-301 doi: https://doi.org/10.21741/9781644900178-25 297 yield of coconut milk was higher because of the effective rupture of cells. Increased pressure in the screw press resulted in increased yield of milk. Fig. 1: Flow sheet for the production of spray dried coconut milk powder. C. Virgin Coconut Oil by Wet Processing The white endosperm portion of coconut is disintegrated and squeezed in screw press to recover coconut milk, which is filtered, and cream is separated by centrifugation. The cream is stirred vigorously to get the virgin coconut oil (VCO) by a process called phase inversion. The oil thus obtained is very clear, nutritious and has a longer shelf life. The residual coconut cake can be dried and sold as medium/low fat desiccated coconut, which may find application in bakery and formulation of low calorie foods. The skim milk obtained from centrifugation can be concentrated and spray dried. The value-added by-products render the whole process quite economical one. Virgin coconut oil (VCO) is prepared from fresh mature coconuts by wet processing without any heat treatment [5]. VCO is colourless and having an intense coconut aroma. It is rich in lauric fatty acid, which is a proven antiviral and anti-bacterial agent. The high-grade VCO has a long shelf life due to presence of natural anti-oxidents in coconut oil. Coconut milk is extracted from deshelled, pared and disintegrated coconuts. Further, coconut Dehusked coconuts 500 kg (1,000 Nuts) Shelling (280 kg) Shells (160 kg) Water (60 kg)