Volume 17, Issue 4

In this study, stabilization was performed using three different oven temperatures (110, (T1) 130 (T2) and 150 °C(T3)) in the oven set at 10% moisture. The effect of stabilization on lipase activity, functional, and thermal properties of rice bran. Lipase activity of control (27.92 U/g) was to be higher than stabilized rice bran samples. Starch gelatinization peak temperature ranged from 70.05 (T3) to 85.09 °C (control). DPPH scavenging effect of control was 12.99 mmol TE. The highest DPPH radical scavenging effect value (15.72 mmol TE) was determined in the T3 sample. ABTS radical scavenging effect of stabilized samples significantly increased ( p  < 0.05) and the increase for T1, T2, and T3 was found to be 73, 75, and 77%, respectively. The highest ferulic (4284 μg/g) and p -coumaric acid (1180 μg/g) contents were determined in T3 and T1 samples, respectively. The content of bound ferulic and p -coumaric acids of stabilized rice bran samples was 2.41 and 2.33 times higher than control samples. While prolamine content was 3.38–4.18 mg/mL; glutelin content ranged from 4.45 to 5.11 mg/mL. An obvious state change during stabilization was observed in all samples around 70–85.9 °C. The results of the study revealed that stabilization might change the functional and thermal properties of rice bran.

Fusarium rot of muskmelon fruit is a common postharvest disease, which not only causes quantity deterioration but also leads to trichothecene accumulation in decay fruits. Neosolaniol (NEO) is one of main trichothecene, which poses a severe threat to human health. In this study, UPLC-MS/MS method was developed to determine NEO in muskmelon inoculated with Fusarium sulphureum . Diatomite was used to remove NEO in muskmelon and the adsorption kinetics, adsorption thermodynamics were analyzed in this adsorption process, and the changes of muskmelon juice quality before and after adsorption were investigated. The results showed that diatomite was a good adsorbent to remove NEO from muskmelon juice. The reaction process fits the Langmuir model and it was spontaneous exothermic reaction and not easy to be desorbed; the kinetic results showed that the maximum adsorption capacity was 12.35 μg/g, and this process fits the Pseudo-second-order model; diatomite had no significant effect on juice quality.

As part of finding a mechanism to ameliorate the decomposition of phytochemicals and antioxidant in drying processing, this research was conducted. To achieve this, pineapple slices was dried using relative humidity (RH) dryer at varied temperature (60–80 °C) combined with RH (10–30%) conditions. The results revealed that higher RH retained with significantly difference ( p <0.05) the phytochemical and antioxidant concentrations and preserved the color and functional groups of dried pineapple under varying drying temperatures. The result also shows that concentrations of these compounds may differ as a result of disparities in the chemical composition which may be worsening by drying conditions such as higher temperature and lower RH. In effect, RH could savage the intensity of losses of these compounds and could therefore play a critical role in drying technology. Practical application: The loss of phytochemicals including polyphenols and antioxidant remains one of the challenging phenomena in drying technology. This research finds ameliorative option for mitigating against the loss of polyphenols and antioxidant by exploring the use of relative humidity (RH). The result shows that RH could savage the intensity of loss of these compounds and could therefore play a critical role in drying technology.

The effects of tri-frequency ultrasound as pretreatment on the peroxidase (POD) inactivation and infrared drying attributes of carrots were studied in the temperature range of 60–80 °C. Thermosonication (TS) treatment reduced 65.21, 73.33 and 81.43% POD activity after 5 min for the temperatures at 60, 70 and 80 °C, respectively, which were all higher than hot water (HW) blanching treated samples. The first-order kinetics fitted well for the POD inactivation curves. Similar retention ranges of vitamin C (VC) were observed after TS (88.41–82.51%) and HW (91.91–88.75%) treatments at the studied range of temperatures. Compared to HW treated samples, drying times of thermosonicated carrot slices were shortened by 13.6, 15 and 15.8% for blanching temperatures at 60, 70 and 80 °C, respectively. The aid of ultrasound showed a positive effect on the rehydration ration (RR) of samples. Sonicated dried samples exhibited higher hardness compared with thermal dried samples. No significant variation ( p  > 0.05) in the total color difference (ΔE) was attained for dried carrot slices pretreated by TS and HW processes.

The effects of chlorogenic acid and quercetin-3-D-galactoside on the decomposition of trimethylamine oxide (TMAO) in squid extract and the main mechanism of inhibition of thermal decomposition were studied. The results indicated that chlorogenic acid and quercetin-3-D-galactoside could inhibit decomposition of TMAO in squid extract. The amount of TMAO was increased by 11.79 and 15.76% in squid extract treated with chlorogenic acid and quercetin-3-D-galactoside from 0 and 2.5 g/L, respectively. The contents of trimethylamine (TMA), dimethylamine (DMA), and formaldehyde (FA) were significantly decreased with increasing contents of chlorogenic acid and quercetin-3-D-galactoside. There were many free radicals in squid extract at high temperatures; however, the free radical signals were weakened after the addition of chlorogenic acid and quercetin-3-D-galactoside therein. This implied that chlorogenic acid and quercetin-3-D-galactoside could inhibit the thermal decomposition of TMAO in squid extract, which was associated with the scavenging of their free radicals. This result provides a theoretical basis for the development and utilization of blueberry leaf extract as an efficient FA inhibitor for aquatic products.

Citrus fiber dispersion with different concentrations (5–25 g/kg) was treated by high-pressure homogenization (90 and 160 MPa) for two cycles. The particle size distribution, hydration properties of powders, morphology and rheological measurements were carried out to study the microstructure and rheological properties changes by high-pressure homogenization (HPH). In conclusion, the HPH can reduce the particle size of fiber, improve the water holding capacity and water binding capacity. Furthermore, fiber shape can be modified from globular cluster to flake-like slices, and tiny pores can be formed on the surface of citrus fiber. The apparent viscosity, storage modulus and loss modulus were increased by HPH whereas the activation energy was reduced. The Hershcel–Bulkley model, Carreau model and Power Law mode were selected to evaluate the rheological properties.

Food thermal properties are essential for calculating freezing time and analyzing energy cost during food freezing or thawing. However, there are currently few data or models of physical properties for foods below −40 °C (e.g., thermal conductivity of food at lower temperatures are lacked due to limitations of device testing below −40 °C). In this paper, the thermophysical parameters of golden pomfret were tested in the temperature range from −100 °C to room temperature. The freezing point was determined. The specific heat and enthalpy of golden pomfret were measured by using a DSC, and the thermal conductivity was measured by a novel self-designed device cooled by a pulse tube cryocooler that can give low temperatures to −253 °C. Finally, the temperature profile obtained by numerical calculation was consistent with experimental results, which proves that predicted models of thermal physical properties in this work will provide reliable data support for the cryogenic freezing of food.

Two-step dry fractionation was employed to prepare the liquefied sheep tail oil at the pilot scale. Sheep tail oil was separated into fat residuals, crude oil, stearin A, stearin B, olein A, and olein B. The extracted rates for crude oil, olein A, and olein B were 66.7, 45.9, and 35.0%, respectively. The ratios of saturated/unsaturated fats in the crude oil, olein A fractions, and olein B fractions were 0.62, 0.63, and 0.60, respectively. The olein B was liquid at ambient temperature and its melting point was 5.32 °C. The iodine values of stearin samples were significantly decreased compared to the crude oil samples ( P  < 0.05). For the stearin fractions, the polymorphic form was mainly β ’ form, and the solid fat content was significantly higher than the olein fractions ( P  < 0.05), which can be used to make the shortening product.