Pomelo (Citrus grandis (L.) Osbeck) is an important cultivar of the Citrus genus, which contains a number of nutrients advantageous to human health. Non-edible parts of pomelo consist of flavedo, albedo, lamella and waste obtained from juice extraction (pulp waste). The peels are also thought to be part of waste products, which generally being discarded. Therefore, the objective of the present study was to evaluate changes in total phenolic contents (TPC) and antioxidant activity of processed pomelo peels after oven drying (50 and 60 °C) and freeze drying treatments in comparison with fresh pomelo peels. A slightly different (4%-6%) in TPC was observed in oven dried pomelo peels in comparison with fresh peels, indicating that there was a slightly effect of post-drying methods on retaining the antioxidant potential of these natural byproducts. In vitro assays revealed that post-drying methods involved oven drying exerted a higher TPC compared to freeze drying in overall parts of pomelo byproducts. Highest retention of bioactive compounds was found in fresh pomelo peels (437-1876 mg GAE/100 g DM), followed by oven dried at 50 and 60 °C (892-1336 mg GAE/100 g DM), and freeze dried (555-1267 mg GAE/100 g DM). In terms of oven dried pomelo byproducts, the highest TPC was retained in albedo (1337 mg GAE/100 g DW), followed by flavedo (1226 mg GAE/100 g DW), lamella (998 mg GAE/100 g DW) and pulp waste (962 mg GAE/100 g DW) respectively. Therefore, oven drying was the most suitable post-drying method to retain the bioactive compounds for pomelo byproducts. This knowledge may inspire consumer or pomelo industry operators to re-evaluate their byproducts, reduce the waste and expand the application of pomelo fruits.

High pressure processing (HPP) is an interesting non-thermal technology that involves the sterilization of food by the mean of ultra-high pressures, which lead to extending the shelf life of processed food, as well as maintaining nutritional value and quality of food products. The consumers' increasing demand for this new products graped the interest of several already-existing high pressure equipment manufacturers around the globe. The successful of this technology encouraged them to enter the field of food processing and adjust their existing technologies to adapt to the new process. This review spots the major discoveries in HPP equipment history, describes the current applications of HHP in processing and provides comprehensive information about HPP equipment technology used in commercial and research applications. In addition, this paper presents the major manufacturers in HPP equipment industry around the world.

a b s t r a c tThe sterilization process in the oil palm mill is a crucial step in extracting and yielding good quality oil. However, this process requires a vast amount of steam to be released to the atmosphere and with that, several attempts in replacing the current steaming sterilization process by means of dry(oven) heating, microwave heating and the invention of a continuous sterilizer were carried out by researchers to provide a greener technology for this purpose. This paper reviewed among the methods and past invention proposed and it can be concluded that the oil yield and the quality depend very much on two major factors, that is the pre-processing conditions and the sterilization and extraction methods used. Bunch strippability is enhanced through the use of continuous sterilizers of low temperature subjected to the fruits. Thorough comparison studies should be done on the current sterilization method and the new techniques introduced since both the current and new methods gave equally good benefits.

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The study aims to investigate the effect of repetitive ultraviolet irradiation (UV-UV) and the combination effect with dimethyl dicarbonate (UV-DMDC-UV) on the physico-chemical properties and microbiological stability of pineapple juice. UV dosages of 10.76 mJ/cm2 percycle and 250 ppm of DMDC were used. There was a significant decrease in turbidity, total phenolic and vitamin C in the treated juices. The UV-UV reported a significant reduction of 1.91 log CFU/ml in total plate count and 1.4 log CFU/ml in yeast and mould. Post addition of DMDC into the UV irradiated juice (UV-UV-DMDC) showed reductions of 2.61 log CFU/ml for TPC and 4.87 log CFU/ml for YM. This study demonstrated the effectiveness of UV irradiation in preserving the nutritional quality and the addition of DMDC can have a combination effect with the UV irradiation of juice in terms of microbial reduction. However, the treatments were not sufficient to achieve adequate microbial reduction as required by the FDA. Industrial relevance: Dimethyl dicarbonate (DMDC) is one of the effective anti-microbial agents that can control a wide range of microorganisms which includes Escherichia coli 0157:H7 and yeast. The effect of dimethyl dicarbonate (DMDC) in reducing microbial counts was significant in this study. According to Threlfall and Morris (2002), DMDC is used to prevent fermentation in excessive yeast contamination in wine production. Moreover, Halim et al. (2012) stated that DMDC has shown promising results for microbial inactivation of fruit juices in a preliminary study in lab. Therefore, combination effect with additives (DMDC) may be able to increase the efficiency of the UV irradiation for microbial reduction in juice and longer the shelf life of juice.

Several parameters related to the physicochemical properties of Josapine pineapple juice, such as moisture content, total soluble solids (TSS), pH, color, water activity, freezing point, sugar content and acidity, were evaluated over a week of ambient storage at 25oC and 52% RH. The results indicated that Josapine pineapples take about 11 days to progress from maturity stage 1 to stage 7. The moisture content of fruit increased from 93.5% wb to 95.1% wb over the 11 days period. Analysis on the color of the juice showed the color space coordinate parameter b varies between 9.11 to 15.8, parameter a increased from –3.33 to –3.68 and the 'L' value decreased from 39.46 to 38.7 at the initial ripening stage but increased to 40.9 in the later stages. The TSS increased at the early ripening stage but decreased toward the end of ripening period. Freezing point, water activity and pH of juice range were –2.77 to – 2.90 oC, 0.988 to 0.997 and 3.81 to 4.10 respectively. The total sugar and acidity in juice range were 12.5 to 17% and 0.69 to 0.90% respectively. The TSS/acid ratio of juice range was 12.32 to 18.60. The data presented in this work demonstrate the relationship between physicochemical properties of Josapine pineapples and the ripening process.

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