Charu Lata Mahanta

Optimisation of phenolic extraction from Averrhoa carambola pomace by response surface methodology and its microencapsulation by spray and freeze drying.

Optimised of the extraction of polyphenol from star fruit (Averrhoa carambola) pomace using response surface methodology was carried out. Two variables viz. temperature (°C) and ethanol concentration (%) with 5 levels (-1.414, -1, 0, +1 and +1.414) were used to design the optimisation model using central composite rotatable design where, -1.414 and +1.414 refer to axial values, -1 and +1 mean factorial points and 0 refers to centre point of the design. The two variables, temperature of 40°C and ethanol concentration of 65% were the optimised conditions for the response variables of total phenolic content, ferric reducing antioxidant capacity and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. The reverse phase-high pressure liquid chromatography chromatogram of the polyphenol extract showed eight phenolic acids and ascorbic acid. The extract was then encapsulated with maltodextrin (⩽ DE 20) by spray and freeze drying methods at three different concentrations. Highest encapsulating efficiency was obtained in freeze dried encapsulates (78-97%). The obtained optimised model could be used for polyphenol extraction from star fruit pomace and microencapsulates can be incorporated in different food systems to enhance their antioxidant property.

Effect of acid concentration and treatment time on acid-alcohol modified jackfruit seed starch properties.

The properties of starch extracted from jackfruit (Artocarpus heterophyllus Lam.) seeds, collected from west Assam after acid-alcohol modification by short term treatment (ST) for 15-30min with concentrated hydrochloric acid and long term treatment (LT) for 1-15days with 1M hydrochloric acid, were investigated. Granule density, freeze thaw stability, solubility and light transmittance of the treated starches increased. A maximum decrease in the degree of polymerisation occurred in ST of 30min (2607.6). Jackfruit starch had 27.1±0.04% amylose content (db), which in ST initially decreased and then increased with the severity of treatment; in LT the effect was irregular. The pasting profile and granule morphology of the treated samples were severely modified. Native starch had the A-type crystalline pattern and crystalline structure increased on treatment. FTIR spectra revealed slight changes in bond stretching and bending. Colour measurement indicated that whiteness increased on treatment. Acid modified jackfruit seed starch can have applications in the food industry.

Relationship of starch changes to puffing expansion of parboiled rice

Abstract‘Intan’ variety of paddy (Oryza sativa) was tested for puffing. It was parboiled under a wide range of paddy moisture content, steaming pressure and time, as also temperature and time of sand heating. The resulting milled rices were studied for their diverse properties including puffing. Indices of starch changes in the samples were calculated as: (1) gelatinisation index from the solubility of amylose in 0.2 N KOH; (2) amylopectin retrogradation from the post-production drop in room-temperature hydration power of the parboiled paddy during air-drying, (3) thermal breakdown of starch from the drop in gel permeation chromatographic fraction I of starch; lipid-amylose complexation indirectly from (4) drop in rate of water uptake during cooking and (5) cooked-rice firmness. It was found that the puffing expansion was very highly correlated with the combined above 5 indices of starch changes, as much as 90% of the variation in puffing being explainable on that basis. Puffing was promoted by gelatinisation as well as lipid-amylose complexation, but was retarded by amylopectin retrogradation and probably starch breakdown.

Traditional Parboiled Rice-Based Products Revisited: Current Status and Future Research Challenges

Abstract Parboiling is an age old technique carried out to improve rice quality. Different grain parboiling techniques have been traditionally followed and scientifically developed for preparation and industrialization of rice. The state of Assam, India produces a large number of rice varieties, some of which are traditionally processed into peculiar parboiled rice products like Hurum, Komal chaul, Bhoja chaul and Sandahguri, which are of both ethnic and possible commercial importances. In spite of extensive research carried out on parboiled rice, these products and their special parboiling techniques have not been sufficiently explored. The status of research on parboiled rice as a whole with special attention to these lesser known speciality products of Assam is extensively reviewed. Future scope of research on these products is also identified.

A comparative study on the effect of conventional thermal pasteurisation, microwave and ultrasound treatments on the antioxidant activity of five fruit juices:

A comparative study on the effect of conventional thermal pasteurisation, microwave and ultrasound treatments on the phytochemical and antioxidant activities of juices from carambola (Averrhoa carambola L.), black jamun (Syzygium cumuni L.Skeels.), watermelon (Citrullus lanatus var lanatus), pineapple (Ananas comosus L. Merr) and litchi (Litchi chinensis Sonn.) was carried out. Depending on the type of fruit sample and treatment, increase or decrease in phytochemical values was observed. Overall, sonication had a positive effect on the total flavonoid content in all the juice samples followed by microwave treatment with exceptions in some cases. High-performance liquid chromatography study showed the presence of different phenolic acids depending on the sample type. The phenolic acids in some processed carambola juice samples showed decrease or complete destruction, while in some cases, an increase or appearance of newer phenolic acid originally not detected in the fresh juice was observed as seen in conventional thermal pasteurisation, microwaved at 600 W and sonicated juices. Both microwaved and sonicated samples were found to have positive effect on the phenolic content and antioxidant activity with exceptions in some cases. Therefore, microwave and sonication treatment could be used in place of thermal pasteurisation depending on the sample requirements.

Physical, physicochemical and nutritional characteristics of Bhoja chaul, a traditional ready-to-eat dry heat parboiled rice product processed by an improvised soaking technique.

Bhoja chaul is a traditional whole rice product processed by the dry heat parboiling technique of low amylose/waxy paddy that is eaten after soaking in water and requires no cooking. The essential steps in Bhoja chaul making are soaking paddy in water, roasting with sand, drying and milling. In this study, the product was prepared from a low amylose variety and a waxy rice variety by an improvised laboratory scale technique. Bhoja chaul prepared in the laboratory by this technique was studied for physical, physicochemical, and textural properties. Improvised method shortened the processing time and gave a product with good textural characteristics. Shape of the rice kernels became bolder on processing. RVA studies and DSC endotherms suggested molecular damage and amylose-lipid complex formation by the linear B-chains of amylopectin, respectively. X-ray diffractography indicated formation of partial B-type pattern. Shifting of the crystalline region of the XRD curve towards lower values of Braggs angle was attributed to the overall increase in inter-planar spacing of the crystalline lamellae. Resistant starch was negligible. Bhoja chaul may be useful for children and people with poor state of digestibility.

Tackling correlated responses during process optimisation of rapeseed meal protein extraction.

Setting of process variables to meet the required specifications of quality characteristics is a crucial task in the extraction technology or process quality control. Simultaneous optimisation of several conflicting characteristics poses a problem, especially when correlation exists. To remedy this shortfall, we present multi-response optimisation based on Response Surface Methodology (RSM)-Principal Component Analysis (PCA)-desirability function approach, combined with Multiple Linear Regression (MLR). Experimental manifestation of the proposed methodology was executed using a multi-responses-based protein extraction process from an industrial waste, rapeseed press-cake. The proposed optimal factor combination reflects a compromise between the partially conflicting natures of the original responses. Prediction accuracy of this new hybrid method was found to be better than RSM alone, verifying the adequacy and superiority of the said approach. Furthermore, this study suggests the feasibility of the exploitation of the waste rapeseed oil-cake for extraction of valuable protein, with improved colour properties using simple, viable process.

Erratum to: Thin layer drying of tomato slices

Erratum to: J Food Sci Technol DOI 10.1007/s13197-011-0397-x The original version of this article unfortunately contained a mistake. Image of Figure 5 has been unintentionally replaced with another image. Correct image of Figure 5 is shown below.

Properties of annealed jackfruit (Artocarpus heterophyllus Lam.) seed starch

Jackfruit seed starch was annealed by single stage and double stage processes and characterised for changes in properties. Single-stage annealing gave higher crystalline order than double-stage annealed starch. No major change in the granular morphology was observed. Annealing resulted in notably altered pasting properties. Increased peak viscosity was indicative of molecular rigidity developed in the granules due to annealing. The increased thermal stability in DSC and specific peak sharpening in the XRD patterns of single-stage annealed starches indicated development of ‘site specific’ crystallinity. The new crystallites formed during the first stage of double-stage annealing were heat labile as crystallinity lowered after the second stage. Single stage annealed jackfruit seed starch can be used for noodle making.

Processing and Utilization of Jackfruit Seeds

Abstract Jackfruit ( Artocarpus heterophyllus Lam.) is a widely found tropical fruit. The fruit bears seed that represents 15–18% of the fruit weight. The seed contains around 55% moisture and is a good source of starch and protein. About 50% of the fruit protein consists of lectins named jacalin that has an adverse effect in the digestive tract. The seed therefore needs to be cooked or processed for consumption. Interest in jackfruit seed has increased as a result of a search for alternative sources of starch. Studies on processing and utilization of jackfruit seed components have not been extensive. Starch is one of the important components of seed and this component has been characterized and studied for effects of physical and chemical modification. The properties of the modified starch reveal its suitability for different end uses. Jackfruit seed starch has high tolerance for thermal and mechanical shear. However, the effect of processing on the phenolic content and antioxidant properties has not been studied.