The melting and crystallization profile of cocoa butter substitute (CBS) formulation consisting of oil blends between palm mid fraction (PMF) and rice bran oil (RBO) were measured through solid fat content using pulsed Nuclear Magnetic Resonance (pNMR) Bruker Minispe. The isothermal melting and crystallization behaviour were determined via Differential Scanning Calorimeter (DSC). The formulations were developed through binary mixture of palm mid fraction and rice bran oil with different ratios created using Mixture Design, Design Expert version 6.0. Selected formulations had been studied for compositional modification through immobilized lipase catalyzed by interesterification using Novozyme® 435. Three selected parameters such as temperature (40-60°C), catalyst concentration (2-10%) and time (4-48 h) at 200rpm orbital shaking with 14 formulations acquired by applying D-Optimal experimental design had been applied. The results showed that blends of 75% palm mid fraction with 25% rice bran oil and its 14 enzymatic interesterification (EIE) yields have the potential to perform the desired behaviour as the crystals are completely melted at 32.48 - 38.28°C. However, the yields of formulation with EIE condition of 60°C, 10% lipase and 48 h incubation time (labeled N) formed the stable β crystals during tempering as it had melting peak at 34.19°C which was closer to the melting point of cocoa butter required in tempering to form V crystals (~34°C), that assured best chocolate appearance and texture.
This study was carried out to determine the effect of super olein (POo) and sunflower oil (SFO) on the rheological properties of chocolate syrup. The formulation of chocolate syrup was modified from that used in a preliminary study consisting of 49.1% water, 30% sugar, 15% cocoa powder, 5% vegetable fats (POo and SFO), 0.5% lecithin and 0.4% vanilla flavour. The rheology of chocolate syrup was measured at a shear rate of 0.01-60 s-1 using a rotational rheometer equipped with a parallel plate at 4°C and 25°C. The shear stress and shear rate data were entered into the Power Law model to determine the apparent viscosity, flow behaviour index (n) and consistency index (K) of the chocolate syrup. In this study, the apparent viscosity of the chocolate syrup was determined at a shear rate of 30 s-1. The apparent viscosity of POo chocolate syrup was the highest at 14.62 ± 1.97 Pa.s (4°C) and 3.91 ± 0.21 Pa.s (25°C), followed by SFO chocolate syrup, with apparent viscosities of 5.42 ± 0.40 Pa.s (4°C) and 1.203 ± 0.076 Pa.s (25°C). The apparent viscosity of Hershey’s chocolate syrup was the lowest, at 2.15 ± 0.070 Pa.s (4°C) and 0.6734 ± 0.027 Pa.s (25°C). All of the chocolate syrups exhibited shear-thinning behaviours with n<1 at 4°C and 25°C. The consistency index of chocolate syrup increased in the order of KHershey
The extraction of pectin from dragon fruit (Hylocereus polyrhizus) peels under three different extraction conditions was identified as an alternative source of commercial pectin. In this work, dried alcohol-insoluble residues (AIR) of dragon fruit peels were treated separately with 0.25% ammonium oxalate/oxalic acid at a pH of 4.6 at 85oC; 0.03 M HCl at a pH of 1.5 at 85oC; and de-ionized water at 75oC. The pectin obtained from these methods was compared in terms of yield, physicochemical properties and chemical structure. Fourier Transform Infrared Spectroscopy (FTIR) was used in the identification of dragon fruit pectins. The results showed that the pectin yield (14.96-20.14% based on dry weight), moisture content (11.13-11.33%), ash content (6.88-11.55%), equivalent weight (475.64-713.99), methoxyl content (2.98-4.34%), anhydrouronic acid (45.25-52.45%) and the degree of esterification (31.05-46.96%) varied significantly (p < 0.05) with the various extraction conditions used. Pectin extracted with ammonium oxalate gave the highest yield of pectin, with high purity and low ash content. Based on the value of methoxyl content and the degree of esterification, dragon fruit pectin can be categorized as low-methoxyl pectin.