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Summary Studies were undertaken to examine the effect of heat treatment on total phenolic content (TPC), colour value (yellowishness and brightness), polyphenol oxidase (PPO) activity and curcuminoid of fresh turmeric rhizome. Fresh turmeric rhizomes were subjected to heat treatment at different temperatures (60–100 °C) for different durations (10–60 min), causing a reduction in browning which was evident from the improved yellowishness and brightness. Activity of PPO was also decreased during heat treatment and PPO was almost inactivated when heated at 80 °C for 30 min. TPC of heat‐treated turmeric after drying (powder) is significantly higher than that after the fresh process. TPC values increased gradually when samples were heated from 60 to 80 °C. At 90 and 100 °C, TPC values were almost identical. Maximum brightness and yellowishness were obtained when the turmeric was heated above 80 °C. Quantitation of curcuminoids in the turmeric sample was made with high performance thin layer chromatography (HPTLC). There was no significant change in the concentration of curcuminoids among the heat‐treated samples. But in the sun‐dried samples, a significant reduction in curcuminoid concentration was observed.

Several pilot-scale trials reported in this paper, using palm stearin-rice bran oil (PS-RBO) blends, obviously did not contain trans FA (TFA), whereas the commercial products were found to contain 18-27% TFA. The effects of processing conditions such as rate of agitation, crystallization temperature, and composition of the blends on the crystal structure of shortenings were studied. The products were evaluated for their physicochemical characteristics using DSC, X-ray diffraction (XRD), HPLC, and and FTIR techniques. The formulation containing 50% PS and 50% RBO showed melting and cooling characteristics similar to those of hydrogenated commercial "vanaspati" samples. Analysis of the FA composition revealed that the formulated shortenings contained 15-19% C 18:2 PUFA. Tocopherol and tocotrienol contents of the experimental shortenings were in the range of 850-1000 ppm with oryzanol content up to 0.6%. XRD studies demonstrated that the crystal form in the shortenings was predominantly the most stable β′ form, and there was less of the undesirable β form.

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