Yanti Maslina Mohd Jusoh

Microwave-Assisted stabilisation and storage stability study of rice bran oil from different varieties

Rice bran is a by-product from milling process of paddy rice to produce refined rice, however until today, there was limited utilisation of rice bran even though rice bran has the ability and potential to become of the major supplementary sources that function as food agent substance. This is due to the instability of rice bran as it will become unstable due to the hydrolysis and oxidation process. The oxidation process, mainly due to the oil presence in the rice bran, releases substances that is unsuitable for consumption. Immediate extraction of the oil from the rice bran is needed as it will be hydrolysed into free fatty acids (FFA) and glycerol by the activity of lipase enzymes. The stabilisation of rice bran can be done by controlling the lipase activity. This process could indirectly prevent the rice bran from being oxidised. Studies have shown that the lipase enzymes in the rice bran can be inactivated depends on the temperature and duration of heat exposure (stabilisation) as well as the moisture content. In this study, the effect of microwave-assisted stabilisation of rice bran was investigated on the quality of rice bran oil (RBO) extracted. Different varieties of rice bran were used in this study which was from lowland, upland and Bario. Extraction of the rice bran was performed using soxtherm extractor and quality of RBO was determined by analysing its properties in terms of crude RBO yield, moisture content and free fatty acid content. Storage stability of the rice bran was evaluated until 40 d. The results demonstrated that the Bario rice bran showed decrease of oil yield from 0 - 40 d with a difference of 48.9 %, followed by the lowland rice bran by 48.7 %. The upland rice bran oil gives the higher different percentage of 64.2 % during the storage. An increase of moisture content was observed during the storage for all stabilised and unstabilised rice brans. Free fatty acid contents show increase amount in almost all types of rice bran range from 2.5 to 11.9 %.

Advanced Natural Food Colorant Encapsulation Methods: Anthocyanin Plant Pigment

Color is one of the major attributes in consumers’ perception toward food quality. Synthetic food colorants are alleged to have links to behavioral and health problems. Due to consumers’ high awareness over the health issues, natural food colorants are the perfect alternative or substitute for the synthetic food colorants. Anthocyanin, a natural pigment, can be found abundantly in fruits and vegetables and its color ranges from bright red to blue. Anthocyanin plant pigments have raised interest due to their ability to be used as natural food colorants with outstanding novel health-promoting properties. Despite its great health potential, anthocyanin has limited application simply due to its instability during processing and storage and also to its unsuitability in various food products. The food industry is continuously looking forward to utilizing the encapsulation technology to improve the natural pigment stability in food products, protect the natural colorant from harsh environmental conditions, promote controlled release, and also to prolong the shelf life of products. The objective of this chapter is to provide a brief overview on encapsulation methods that have been used for anthocyanins, including spray-drying, freeze-drying, and most recently, the microwave-assisted encapsulation. The source, stability, color variation, and application of anthocyanins in food products are also briefly discussed.

Optimisation of radio frequency assisted extraction of apple peel extract: Total phenolic contents and antioxidant activity

The objective of this study is to determine the optimum operating conditions of apple peel extraction process using a novel extraction method known as radio frequency assisted extraction (RFAE). Apple peel extract with the highest total phenolic contents and antioxidant activity is targeted in this study. RFAE is a green extraction method which operates based on the dielectric heating concept. Response surface methodology was employed for designing the experiment, analysing the effects and optimising the extraction conditions for RFAE of apple peel phenolic compounds. The effects of ethanol concentration (10 - 70 %), mixing speed (10 - 320 mL N2/min), solid to liquid ratio (0.002 - 0.02 g/mL) and RF power (200 - 400 W) on total phenolic compounds and DPPH radical scavenging activity efficiency were investigated in order to understand and improve the RFAE performance. All processing parameters exert significant effects on the total phenolic compounds and radical scavenging activity of the apple peel extract. The highest recovery of TPC with a value of 121.87 mg GAE/ g DW can be achieved if the extraction is performed using 42.67 % ethanol concentration, mixing speed of 320 mL N2/min, solid to liquid ratio of 0.0114 g/mL and power at 400 W. The maximum value of DPPH (94.54 %) can be achieved if the extraction is performed using an ethanol concentration, mixing speed, solid to liquid ratio and power of 37.33 %, 165 mL N2/min, 0.02 g/mL and 400 W.

Effects of Ingredients Ratio on Physicochemical Properties of Convective-microwave Nutritious Dried Rice Meal

During emergency situation, such as natural disasters or war, diseases outbreak can occur due to lack of nutrition. Due to this issue, a wholesome dried rice meal (DRM) was conceptualised as emergency, quick, nutritious, functional and comforting food for natural disaster and war victims, particularly during the critical period of post-disaster or war period. The DRM was designed so that it can be consumed as dried cracker or semi-solid porridge. The objective of this study was to evaluate the effect of rice (100 g and 200 g), minced chicken meat (30 g and 40 g) and mixed vegetables (25 g and 35 g) ratio on the energy content, vitamin C, and expansion ratio of convective-microwave DRM. The convective-microwave drying method was chosen for DRM preparation to obtain the final product with specific puffing condition which enhances rehydration process and also to shorten the total production time of DRM. The experiments were conducted using factorial design. The experimental results showed that the highest DRM energy content of 1.60 kCal could be achieved by cooking 200 g rice with 40 g minced chicken meat and 25 g mixed vegetables. The DRM with highest vitamin C content of 0.018 g was achieved using 100 g, 30 g minced chicken meat and 25 g mixed vegetables. The DRM with the highest expansion ratio of 1.13 was achieved using 100 g rice, 30 g minced chicken meat and 25 g mixed vegetables. Empirical models for predicting energy contents, vitamin C and expansion ratio of the DRM were also obtained.

Physicochemical Properties and Storage Stability of Margarine Containing Anthocyanins from Roselle Calyces

Addition of encapsulated anthocyanins in margarine formulation improves the stability of margarine. In this study, investigation on the storage and stability characteristics of water-in-oil emulsion, i.e. margarine, containing encapsulated or non-encapsulated anthocyanins from Roselle was carried out. Encapsulation of anthocyanins was performed using microwave-Assisted technique to study the dispersion and stability of anthocyanins in the margarine. Margarines were formulated with three different oil-To-Aqueous ratios (88:12, 86:14 and 84:16). The blend formulation was compared with commercial margarine and the stability of the margarine was determined by using chemical, physical and texture stability analysis and. Margarine containing non-encapsulated anthocyanin showed improved stability compared with encapsulated anthocyanin.

Efficiency and thermal stability of encapsulated anthocyanins from red dragon fruit (Hylocereus polyrhizus (Weber) Britton & Rose) using microwave-assisted technique

Anthocyanins are one of the commonly used natural colorants for beverages, confectionary, fruit preparation and ice cream. Strong antioxidant activity of these anthocyanins has attracted great interest to the food industry. The instability of anthocyanins through the factors such as light, pH, temperature and oxygen has given problem during processing and storage of these compounds. One of the approaches to overcome this problem is by encapsulating the material using wall material. This study was conducted to investigate the efficiency of encapsulation of anthocyanins from red dragon fruit (Hylocereus polyrhizus (Weber) Britton & Rose) using microwave-assisted technique with different drying times and thermal stability of the encapsulated anthocyanins. Encapsulated anthocyanins were produced in form of powder using maltodextrin as the wall material. The encapsulation drying time were varied from 1 min to 3 min with fixed power, 330W. The encapsulated anthocyanins were analyzed in effect of thermal heating (60°C and 80°C). The results indicated that, at different encapsulation drying time, 2 min capsule showed the highest yield of encapsulation where 3 min capsule showed the highest encapsulation efficiency followed by 2 min capsule with 4% differences. From this study the encapsulation at 2 min drying time showed the most feasible encapsulation process. Thermal study at 60°C and 80°C showed that anthocyanins degraded faster at higher temperature, 80°C for all capsule types.