Antioxidant Activity of Rambutan (Nephelium lappaceum L.) Peel Extract in Soybean Oil during Storage and Deep Frying

Rambutan (Nephelium lappaceum L.) peel (RBP) is discarded as the main by‐product during processing of the fruit. Increasing attention is now paid to the valorization of RBP for the recovery of valuable compounds. Geraniin, ellagic acid, quercetin, and rutin are the main phenolic compounds found in methanolic RBP extract. Extracted rambutan peel powder (ERPP) is used to evaluate the oxidative stability of soybean oil stored at 4 and 30 °C in the dark and light and deep fried with potatoes at 160 °C. Tert‐butylhydroquinone (100 µg g^?1 oil, TBHQ) serves as positive control. Oil supplemented with ERPP of 1000 µg gallic acid equivalents (GAE) g^?1 of oil shows positive effects on the retardation of the oxidation process during storage in comparison with oil without addition. During deep frying, either ERPP (1000 µg GAE g^?1) or TBHQ retards the lipid oxidation of oil. Levels of thiobarbituric acid reactive substances of potatoes fried in oil fortified with the extract and TBHQ (0.4–0.59 µg g^?1) are much lower than those without the extract (1.31 ± 0.10 µg g^?1) (p < 0.05). Therefore, RBP extract exhibits favorable antioxidant effects and can be used for effectively inhibiting lipid oxidation in oil during storage and deep frying. Practical Applications: An extract from rambutan fruit peel containing phenolic compounds, that is, geraniin, ellagic acid, rutin, and quercetin showed promising results to be used as potential antioxidants in soybean oil during deep frying. Both oxidation of the frying oil as well as the oxidation of the food product, that is, potatoes were inhibited. These results demonstrated that rambutan fruit peel extract can be used as a natural antioxidant in frying oil to replace synthetic antioxidants, that is, TBHQ.     

Thermal inactivation kinetics of alkaline phosphatase in equine milk

Alkaline phosphatase (ALP) is widely used as an indicator of proper pasteurization in bovine milk. Due to interest in the use of equine ALP as a time/temperature integrator (TTI) for evaluation of the efficacy of thermal processing of equine milk, its inactivation kinetics were evaluated in whole and skimmed equine milk. Experimentally determined decimal reduction times showed that equine ALP is more readily inactivated in equine milk than its bovine counterpart. Thus, considering the required 6 D reduction of pathogens and the rather low enzyme level present in equine milk, equine ALP will not be suitable as indicator for correct pasteurization of equine milk under the conditions currently used in the reference method for the determination of ALP in milk-based products.     

Compression resistance and hysteresis of carbon fibre tows with grown carbon nanotubes/nanofibres

Growth of carbon nanotubes (CNT) or carbon nano-fibres (CNF) on fibrous substrates is a way to increase the fracture toughness of fibre reinforced composites (FRC), with encouraging results reported in the recent years. The issues for these materials related to manufacturing of these composites are, however, less investigated. Following the study of compressibility of woven carbon fibre preforms with CNT/CNFs grown on the fibres using the CVD method [Compos Sci Technol 2011; 71(3): 315-325], this paper describes compression tests on the carbon tows used in these fabrics. The results of the measurements include pressure vs. thickness diagrams in consecutive compression cycles and hysteresis of the compression. The results confirm a drastic change of compressibility of fibrous assemblies in the presence of CNT/CNF grafting.     

Is the Jaw Bone Micro-Structure Altered in Response to Osteoporosis and Bisphosphonate Treatment? A Micro-CT Analysis

The aim of the study was to quantify the micro-architectural changes of the jaw bone in response to ovariectomy, exposed or not to bisphosphonate treatment. A total of 47 Wistar rats were ovariectomized (OVX) or sham-operated (shOVX) and exposed to osteoporosis preventive treatment for eight weeks either with bisphosphonates (alendronate, ALN; group OVX-ALN) three days/week at a dose of 2 mg/kg or with saline solution (untreated control condition; group OVX). The bone morphometric parameters of the trabecular jaw bone were assessed using ex vivo micro-computed tomography. The regions of interest investigated in the maxilla were the inter-radicular septum of the second molar and the tuber. The regions quantified in the mandible included the three molar regions and the condyle. A one-way analysis of variance followed by pairwise comparison using Tukey’s HSD and the Games–Howell test was conducted to explore significant differences between the groups. In the maxilla, OVX decreased the bone volume in the inter-radicular septum of the second molar. Bisphosphonate treatment was able to prevent this deterioration of the jaw bone. The other investigated maxillary regions were not affected by (un)treated ovariectomy. In the mandible, OVX had a significant negative impact on the jaw bone in the buccal region of the first molar and the inter-radicular region of the third molar. Treatment with ALN was able to prevent this jaw bone loss. At the condyle site, OVX significantly deteriorated the trabecular connectivity and shape, whereas preventive bisphosphonate treatment showed a positive effect on this trabecular bone region. No significant results between the groups were observed for the remaining regions of interest. In summary, our results showed that the effects of ovariectomy-induced osteoporosis are manifested at selected jaw bone regions and that bisphosphonate treatment is capable to prevent these oral bone changes.     

Short communication: Validation of a novel milk progesterone-based tool to monitor luteolysis in dairy cows using cost-effective,on-farm measured data

The progesterone (P4) monitoring algorithm using synergistic control (PMASC) uses luteal dynamics to identify fertility events in dairy cows. This algorithm employs a combination of mathematical functions describing the increasing and decreasing P4 concentrations during the development and regression of the corpus luteum and a statistical control chart that allows identification of luteolysis. The mathematical model combines sigmoidal functions from which the cycle characteristics can be calculated. Both the moment at which luteolysis is detected and confirmed by PMASC, as well as the model features themselves, can be used to inform the farmer on the fertility status of the cows.     

The effect of inoculum size on the growth of Penicillium expansum in apples

Penicillium expansum is the most important cause of blue mould rot, a major post-harvest disease of apples worldwide. The objective of this study was to evaluate the effect of the inoculum size on the germination and growth parameters of P. expansum under different storage conditions in apples. Growth of P. expansum was observed in more than 90% of the inoculations, when the inoculum was equal or higher than 2x10(4) spores. The use of a low inoculum level resulted in longer lag phases and a larger variability of the estimated lag phase. This indicates that more replications are necessary to estimate the lag phase of the mould in the specified circumstances. At lower temperature, more inoculum was necessary to reduce the variability of the estimated lag phase, showing that this effect is temperature dependent. Moreover, the effect of the inoculum level on the lag phase is even more pronounced for a slower growing strain. These results imply that the inoculum size influences the estimated growth parameters and should be considered in quantitative risk assessments and for the design of challenge tests and experiments to gather data for predictive growth models.     

Promoting structure formation by high pressure in gluten-free flours

In order to evaluate the potential of high pressure (HP) treatment to improve the functional properties of gluten-free flours, the effect of HP on the rheological properties of three gluten-free batters was investigated. Buckwheat, white rice and teff batters (40 g/100 g) were treated for 10 min at 200, 400 or 600 MPa. Changes in the microstructure of the batters after HP-treatment were observed using scanning electron microscopy. Pasting profiles revealed HP-induced starch gelatinisation. Furthermore, Lab-on-a-Chip capillary gel electrophoresis revealed protein polymerisation by thiol/disulphide-interchange reactions in white rice and teff batters. For buckwheat proteins however, no such cross-linking mechanism was observed, which was explained by the absence of free sulfhydryl groups. An increase in viscoelastic properties at higher pressures was observed, and could be explained by the modifications occurring in starch and protein structure. Overall, this study has shown that HP-treatment has the potential to improve functional properties of gluten-free batters.