Original article Enzymatically modified tea seed oil as cocoa butter replacer in dark chocolate Soheila Zarringhalami, Mohammad Ali Sahari,* Mohsen Barzegar & Zohreh Hamidi-Esfehani Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, PO Box 14115-336, Tehran, Iran (Received 27 July 2009; Accepted in revised form 11 December 2009) Summary Cocoa butter replacer (CBR) was prepared by enzymatic interesterification of hydrogenated and solid fraction (SF) of tea seed oil at weight percent ratio of 30:70, using sn-1,3 specific lipase from Thermomyces lanuginosus. Dark chocolate samples were then prepared with the prepared CBR as a replacement for 5%, 10%, 15% and 20% of cocoa butter (CB) and the effect of the replacement on hardness (as a key quality factor in chocolate) of the chocolate samples was investigated. Results showed that chocolate samples containing 5% and 10% of interesterified sample (EIS), had the closer texture to that of CB chocolate than other samples. The solid fat content (SFC) profiles also revealed that blending 10% of EIS with CB in chocolate formulation dose not affect the sharp melting point of CB. Based on the results taken from bloom formation, polymorphic structure and sensory evaluation, adding up to 10% of EIS in chocolate formulation reduces the bloom development without adverse affecting the desirable b crystal formation and sensory qualities in the chocolate samples. Keywords Cocoa butter replacer, dark chocolate, enzymatic interesterification, tea seed oil. Introduction Cocoa butter (CB), the natural fat extracted from the cocoa beans, is one of the most important ingredients used in chocolate and confectionary industries. CB is characterised by desirable physico-chemical properties resulting from its unique triacylglycerol species (TAGS). Depending on the origin of CB, its typical TAGS are as: approximately 42.2% 1(3) palmitoyl-3(1) stearoyl-2- oleoglycerol (POS), 24.2% 1(3)-distearoyl-2-oleoylglyc- erol (SOS) and 21.8% 1,3-dipalmitoyl-2-oleoylglycerol (POP), with oleic acid in sn-2 position of glycerol backbone (Simoneau et al., 1999). These symmetrical TAGS induce the sharp melting point of CB just below body temperature, which is what cause chocolate to remain solid and hard at room temperature but melt completely and fast in mouth (Liu et al., 2007). But, limited supply and high price of CB lead to modify other lower value fats or oils to produce CBR. CBR is a general term applying to those sorts of fats which are being adopted as partially or wholly substitutes for CB in chocolate formulation (Zaidul et al., 2006). Replacing a part of CB with CBRs in chocolate products is of a great interest from economical perspectives (Kurvinen et al., 2002). In Iran, tea seed is considered as a by-product, while several studies show its oil content is around 30–32% with the high quality resemblances to olive oil (Sahari et al., 2004). However, tea seed oil, like any other kind of vegetable oils, has only limited commercial applica- tions in its original form. Modification of some com- mercial fats and oils by enzymatic interesterification has been studied widely as a useful tool in producing CBRs over recent years (Khumalo et al., 2002), yet there are just few researches reported on producing CBR from tea seed oil. In the first part of the present study, the blend of hydrogenated and SF of tea seed oil was subjected to enzymatic interesterification to produce a structured lipid as CBR in order to use in dark chocolate formulation. To choose the appropriate chocolate for- mulation, the effect of various levels of CB replacement on chocolate quality is investigated at in the second part of this study. Materials and methods Materials Tea seeds (Lahijan variety), were collected from Iranian farms in Lahijan (located in the northern part of Iran). Lypozim TL IM (1,3-specific lipase), a silica granulated Thermomyces lanuginosus, and *Correspondent: Fax: +98 21 44196524; e-mail: sahari@modares.ac.ir International Journal of Food Science and Technology 2010, 45, 540–545 540 doi:10.1111/j.1365-2621.2009.02162.x Ó 2010 The Authors. Journal compilation Ó 2010 Institute of Food Science and Technology