Transparency phenomena of flat-rice noodles (kuew teow) at drying at soaking variation

This paper presents a transparency phenomenon that occurred in hot air and heat pump dried flat-rice noodles, which is explained by the higher colour changes, glassy puffing microstructures, and lower fat content in comparison to the freeze dried flat-rice noodles. Hot air drying and heat pump drying recorded the colour changes at an average of 43.87 ± 1.5 twice than colour change caused by freeze drying at 19.33 ± 1.12 to verify the transparency caused by employing high temperature to eventually increase the sample lightness. However, the microstructures study suggested that freeze drying produced distinct pores ranging from 2.05 μm to 27.68 μm whereby hot air drying and heat pump drying merely produced glossy transparent texture. Indeed, the pores disclose the fat content recorded by freeze drying in flat-rice noodles at 5.62% ± 0.2 twice than the fat content recorded by hot air and heat pump drying at 2.48% ± 0.49. Therefore, by learning the transparency phenomenon in hot air and heat pump dried noodles approves that freeze drying eventually preserves the quality attributes of flat-rice noodles as closest to the fresh flat-rice noodles in terms of colour, microstructures, and fat content

Anthocyanin recovery from mangosteen (Garcinia mangostana L.) hull using lime juice acidified aqueous methanol solvent extraction

The recovery of anthocyanin from mangosteen (Garcinia mangostana L.) hull was investigated using an aqueous methanol solvent acidified by Mexican lime (Citrus aurantifolia Swingle) juice in comparison with the conventional HCl acidified methanol solvent. The addition of 0.20 mL lime juice/mL to an aqueous methanol extraction solvent gave a maximum total monomeric anthocyanin (TMA) recovery of 4.742 ± 0.590 mg cy-3-glu/g hull powder compared to 2.950 ± 0.265 when using an HCl acidified extraction solvent at 0.20%. This acidified aqueous methanol extraction solvent using lime juice produced an increase of 60.75% anthocyanin which suggests that this natural lime juice can be a good acidifying agent. The quantity of lime juice or HCl added to the extraction solvent was found to be a more important factor than its pH value in influencing TMA yield. A lower particle size of hull powder of 250 μm to 500 μm was also found to give the highest recovery of anthocyanin (p < 0.05)

Molecular identification of species and production origins of edible bird's nest using FINS and SYBR green I based real-time PCR

The increasing demand and consumption of edible bird's nest (EBN) by people worldwide has contributed to the food fraud issue. To ensure the authenticity of EBN in regard to their origin, rapid and accurate analytical methods are very much needed. In this study, forensically informative nucleotide sequencing (FINS) technique based on mitochondrial and nuclear DNA sequences, and phylogenetic analysis was performed to identify the species and production origins of raw and commercial EBNs. The cytochrome b (Cyt b), NADH dehydrogenase subunit 2 (ND2), 12S ribosomal RNA and beta-fibrinogen intron 7 gene markers used were able to identify and classify EBN produced by Aerodramus fuciphagus and Aerodramus maximus. It was newly discovered that EBN from man-made houses and natural caves were genetically differentiable using the mitochondrial Cyt b and ND2 genes. The phylogenetic results revealed that all EBN samples were well-separated into two groups following their species origin and production origin. A rapid and cost-effective identification alternative of SYBR green I based real-time PCR assay targeting a 177 bp of the mitochondrial Cyt b gene was developed and it efficiently differentiated genuine EBN from counterfeits. This FINS and SYBR green I based real-time PCR are highly sensitive, specific and reliable methods for identification of EBN origins and could be useful for preventing fraud substitution and mislabelling of EBN to ensure food safety

A comparative quality study and energy saving on intermittent heat pump drying of Malaysian edible bird's nest

This paper aims to study the influence of temperature and relative humidity (RH) during intermittent heat pump drying at 28.6–40.6°C, 16.2–26.7% RH, α = 0.2–1.0, and the comparison was made against fan drying (27°C, 39.7% RH, α = 1.00). It was observed that the effects of temperature and RH on drying rate were significant when moisture content was high. Experimental results showed that intermittent heat pump drying at 28.6°C, 26.7% RH, α = 0.2 of edible bird’s nest greatly reduced effective drying time by 84.2% and color change compared to fan drying, and retained the good energy efficiency

Kinetic retention of sialic acid and antioxidants in Malaysian edible bird's nest during low-temperature drying

Drying is one of the essential processing steps for dried edible bird’s nest; however, sialic acid and antioxidant can be highly thermosensitive and unstable. Therefore, aim of this study was to determine the degradation kinetics of sialic acid and antioxidants during low-temperature drying at 25–40°C as compared to conventional hot air-drying at 70°C. These compounds’ degradation exhibited first-order kinetics. Sialic acid and antioxidant retentions were 83.9 and 96.6%, respectively, at 25°C, and 78.7 and 91.5% at 40°C, respectively, by low-temperature drying; while, 42.5 and 38.7%, respectively, at 70°C by conventional hot air-drying. Finally, empirical models were significantly fitted to predict sialic acid and antioxidant retention as edible bird’s nest reached a certain level of drying, which may be useful from the processing standpoint and validate the usage of low-temperature drying as a process tool for retention of sialic acid and antioxidant in edible bird’s nest

Retention of sialic acid content in Malaysian edible bird's nest by heat pump drying

This paper presents the results of an experimental attempt to improve the drying kinetics for the retention of colour and sialic acid in edible bird’s nest through heat pump drying. Kinetics of hot air drying and heat pump drying were studied by performing various drying trials on edible bird’s nest. Isothermal drying trials were conducted in hot air drying and heat pump drying at a temperature range of 40 °C-90 °C and 28.6 °C-40.6 °C, respectively. Intermittent drying trials were carried out in heat pump drying with two different modes, which are periodic air flow supply and step-up air temperature. Experimental results showed that heat pump drying with low temperature dehumidified air not only enhanced the drying kinetics but also produced a stable final product of edible bird’s nest. Heat pump-dried edible bird’s samples retained a high concentration of sialic acid when an appropriate drying mode was selected

Kinetics of mass transfer, colour, total polyphenol and texture change of Manilkara zapota during convective air drying

The effects of air temperature and product size on drying kinetics, retained total polyphenol content (TPC), hardness kinetics and total colour change (ΔE) kinetics of ciku (Manilkara zapota) were investigated. In addition, five terms of the theoretical model were used to estimate the effective diffusivity values during drying at temperatures from 40°C to 70°C. The drying rates of dried ciku were increased with increasing temperature and decreasing product size. It was found that hardness of ciku dried at temperature higher than 60°C increased significantly, when the moisture content was reduced to less than 0.5 g H2O/g DM (dry basis). In terms of nutritional value, the retained total polyphenol content (TPC) of dried ciku in hot air drying also increasing with temperature. The highest retained TPC was 141 mg GAE/ 100g of samples, which can be obtained from drying at 70°C

Drying kinetics, texture, color, and determination of effective diffusivities during sun drying of chempedak

Sun drying of chempedak (Artocarpus integer) was carried out on different sample sizes to investigate the effects on product quality. Fick's second law model was used to determine the effective diffusivities of sun–dried chempedak slabs based on the drying rate versus moisture content plots. In addition, texture degradation and total color changes were investigated. The texture and color changes of dried chempedak were relatively significant (p < 0.05) compared to fresh chempedak. There was an increase in dried fruit hardness and chewiness but a decrease in springiness and cohesiveness during drying

Drying models and quality analysis of sun-dried ciku

Sun drying of ciku (Manilkara zapota) was carried out on different sample sizes to investigate the effects on drying kinetics. It was found that the maximum drying rates of sun-dried ciku decreased with larger product size. Three sunny days are needed to dry the ciku slabs to an average final moisture content of 0.2 g H2O/g dry mass. The results showed that hardness and chewiness of the dried samples were significantly different (p 0.05) compared to fresh ciku slabs. In addition, sun-dried ciku retained a total polyphenol content (TPC) that was relatively low (p < 0.05) compared to fresh ciku

Liquid Biphasic Electric Partitioning System as a Novel Integration Process for Betacyanins Extraction From Red-Purple Pitaya and Antioxidant Properties Assessment

Nowadays, downstream bioprocessing industries inclines towards the development of a green and high efficient bioseparation technology. Betacyanins are presently gaining higher interest in the food science as driven by their high tinctorial strength and health promoting functional properties. In this study, a novel green integration process of liquid biphasic electric partitioning system (LBEPS) was proposed for betacyanins extraction from peel and flesh of red-purple pitaya. Initially, the betacyanins extraction using LBEPS with initial settings was compared with that of liquid biphasic partitioning system (LBPS), and the results revealed that both systems demonstrated a comparable betacyanins extraction. This was followed by further optimizing the LBEPS for better betacyanins extraction. Several operating parameters including operation time, voltage applied, and position of graphitic electrodes in the system were investigated. Moreover, comparison between optimized LBEPS and LBPS with optimized conditions of electric system (as post-treatment) as well as color characterization and antioxidant properties assessment were conducted. Overall, the betacyanins extraction employing the optimized LBEPS showed the significant highest values of betacyanins concentration in alcohol-rich top phase (Ct) and partition coefficient (K) of betacyanins from peel (99.256 ± 0.014% and 133.433 ± 2.566) and flesh (97.189 ± 0.172% and 34.665 ± 2.253) of red-purple pitaya. These results inferred that an optimal betacyanins extraction was successfully achieved by this approach. Also, the LBEPS with the peel and flesh showed phase volume ratio (Vr) values of 1.667 and 2.167, respectively, and this indicated that they have a clear biphasic separation. In addition, the peel and flesh extract obtained from the optimized LBEPS demonstrated different variations of red color as well as their antioxidant properties were well-retained. This article introduces a new, reliable, and effective bioseparation approach for the extraction of biomolecules, which is definitely worth to explore further as a bioseparation tool in the downstream bioprocessing