Targeted use of LEDs in improvement of production efficiency through phytochemical enrichment

Based on available literature, ecology and economy of light emitting diode (LED) lights in plant foods production were assessed and compared to high pressure sodium (HPS) and compact fluorescent light (CFL) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco‐friendly lighting devices. The present review indicates also that LEDs have many practical benefits compared to other lamp types. In addition, they are applicable in many purposes in plant foods production. The main focus of the review is the targeted use of LEDs in order to enrich phytochemicals in plants. This is an expedient to massive improvement in production efficiency, since it diminishes the number of plants per phytochemical unit. Consequently, any other production costs (e.g. growing space, water, nutrient and transport) may be reduced markedly. Finally, 24 research articles published between 2013 and 2017 were reviewed for targeted use of LEDs in the specific, i.e. blue range (400–500 nm) of spectrum. The articles indicate that blue light is efficient in enhancing the accumulation of health beneficial phytochemicals in various species. The finding is important for global food production. © 2017 Society of Chemical Industry     

Metabolic effects of lactoferrin during energy restriction and weight regain in diet-induced obese mice

Lactoferrin (LF) is an iron-binding glycoprotein exerting several physiological functions such as antimicrobial activity, modulatory effects on lipid metabolism and anti-inflammatory properties. We examined whether LF prevents diet-induced obesity and development of fatty liver formation in C57Bl/6J mice. Lactoferrin (15% of dietary casein replaced by LF) enhanced weight loss and decreased body fat content during energy restriction compared to casein without influencing energy intake. During the ad libitum feeding after weight loss, LF suppressed weight regain and protected against the development of fatty liver formation compared to casein without influencing energy intake or fecal fat excretion. During the weight regain phase LF also improved glucose tolerance, decreased skeletal muscle leptin mRNA expression, and ameliorated adipose tissue inflammation. In conclusion, LF supplementation enhances the outcome of weight loss and subsequent weight regain, ameliorates fatty liver formation, and exerts beneficial effects on glucose tolerance and adipocyte tissue inflammation without interfering energy intake.     

Separation and concentration of bilberry impact aroma compound from dilute model solution by pervaporation

BACKGROUND: In the present work, the flavor compounds of natural juice of bilberries were qualitatively analyzed by GC‐MS, leading to the identification of trans‐Hex‐2‐en‐1‐ol as one of the major ‘impact aroma’ compounds of this fruit. The pervaporation of trans‐Hex‐2‐en‐1‐ol from diluted aqueous solutions was studied using commercial polydimethylsiloxane (PDMS) capillary membranes. The influences of solvent composition (water/ethanol mixtures), initial concentration of the aroma compound, flow rate and temperature of the feed were studied. RESULTS: High selectivity of the PDMS membrane towards the aroma compound was obtained, leading to enrichment factors in the range 100 < β < 200. Mass transfer resistance was found to be located in the pervaporation membrane. Experimental data showed a linear dependency of the permeation flux of trans‐Hex‐2‐en‐1‐ol on the differences in partial pressures of the compound across the pervaporation membrane. The permeability coefficient of the PDMS membrane to the transport of trans‐Hex‐2‐en‐1‐ol was calculated as P_{m, Hex}(50 °C) = 7.62 × 10^?11 mol m^?1 s^?1 Pa^?1. CONCLUSION: The membrane used was found to be very selective toward trans‐Hex‐2‐en‐1‐ol. A model based on the solution‐diffusion mechanism was applied. The mass transfer parameters needed for the design of a pervaporation process for aroma compound recovery were obtained. Copyright © 2008 Society of Chemical Industry     

Enzymatic cross-linking of β-lactoglobulin in solution and at air-water interface: Structural constraints

Effective and controlled use of cross-linking enzymes in structure engineering of food systems depends on characterization of the favorable conditions for enzyme-substrate complex and the limiting factors for the desired modification. In this respect, we analyzed the susceptibility of bovine β-lactoglobulin (BLG) to enzymatic cross-linking by Trichoderma reesei tyrosinase (TrTyr) and transglutaminase (TG). Changes in BLG molecular structure were determined at pH 6.8, 7.5 and 9.0 before and after high-temperature heat treatment. The conformational change was linked to efficiency of protein cross-linking. BLG was not susceptible to TrTyr without heat treatment. TG, however, induced inter-molecular cross-links at pH 7.5 and 9.0. After the heat treatments, BLG molecules adopted a molten-globule-like conformation. Both of the enzymes were able to form inter-molecular cross-links between heat-denatured BLG molecules. Electrophoretic mobility and broadness of the oligomer bands created by both enzymes on SDS-PAGE gels showed differences which were linked to the availability and number of target amino acid residues. Evidence for intra-molecular cross-linking was obtained. Once adsorbed to air/water interface, BLG formed a viscoelastic surface film which was characterized by surface shear rheology. Application of cross-linking enzymes under a dense layer of BLG molecules at the interface led to decreasing G′ with time. Intra-molecular links were most probably favored against inter-molecular on packed BLG layer leading to constrained molecules. Results in general emphasize the importance of structural and colloidal aspects of protein molecules in controlling inter/intra-molecular bond formation by cross-linking enzymes.     

The Effect of Biofuel Originated Potassium and Sodium on the NH3-SCR Activity of Fe–ZSM-5 and W–ZSM-5 Catalysts

The effect of potassium, sodium and water on Fe–ZSM-5, W–ZSM-5 and ZSM-5 catalysts was investigated. Catalysts were characterized by several techniques and tested in the NH₃-SCR reaction. The impact of water-, K- and Na-treatments on the activity of catalysts was negligible. Thus, the catalysts can be concluded to be resistant to K- and Na-treatments.     

Effect of pectinolytic juice production on the extractability and fate of bilberry and black currant anthocyanins

Bilberries (Vaccinium myrtillus L.) and black currants (Ribes nigrum L.), dark blue berries rich in anthocyanins, were processed with an aid of commercial pectinolytic enzyme preparations, and the effect of processing on berry anthocyanins was investigated. The enzyme preparations were dosed based on their polygalacturonase activity from 1 to 100 nkat/g of berry mash. The juice yields were determined by weighing, and anthocyanin analyses were performed with HPLC. The bilberry and black currant juice yields increased significantly in enzyme-aided treatments with comparison to control, even with the lowest (1 nkat/g) polygalacturonase dosage. The anthocyanin yield increased by up to 83% for bilberries and up to 58% for black currants in enzyme-aided treatments as compared to control. The results showed that higher polygalacturonase dosage was needed for black currant to achieve the maximal juice and anthocyanin yields than for bilberries. The stability and the profile of extracted anthocyanins were greatly affected by the glycosidase side activities present in the enzyme preparations, which were able to hydrolyze certain anthocyanins to the corresponding aglycones. In addition, the data indicate that anthocyanidin rutinosides were more easily extracted than those of glucosides, which prevailed over the arabinosides and galactosides. Thus, prior to processing it is important to know the intact anthocyanin structures of the raw material, and the activity profile of the enzyme preparation to obtain optimal anthocyanin extractability and enzyme dosage.     

Comparison of catalytic activity and selectivity of Pd/(OSC + Al2O3) and (Pd + OSC)/Al2O3 catalysts

The effect of the Pd addition method into the fresh Pd/(OSC + Al₂O₃) and (Pd + OSC)/Al₂O₃ catalysts (OSC material = Ce_xZr_1−xO₂ mixed oxides) was investigated in this study. The CO + NO and CO + NO + O₂ model reactions were studied over fresh and aged catalysts. The differences in the fresh catalysts were insignificant compared to the aged catalysts. During the CO + NO reaction, only small differences were observed in the behaviour of the fresh catalysts. The light-off temperature of CO was about 20 °C lower for the fresh Pd/(OSC + Al₂O₃) catalyst than for the fresh (Pd + OSC)/Al₂O₃ catalyst during the CO + NO + O₂ reaction. For the aged catalysts lower NO reduction and CO oxidation activities were observed, as expected. Pd on OSC-containing alumina was more active than Pd on OSC material after the agings. The activity decline is due to a decrease in the number of active sites on the surface, which was observed as a larger Pd particle size for aged catalysts than for fresh catalysts. In addition, the oxygen storage capacity of the aged Pd/(OSC + Al₂O₃) catalyst was higher than that of the (Pd + OSC)/Al₂O₃ catalyst.     

Milk protein-derived bioactive tripeptides Ile-Pro-Pro and Val-Pro-Pro protect endothelial function in vitro in hypertensive rats

Milk products containing casein-derived bioactive tripeptides Ile-Pro-Pro (isoleucine-proline-proline) and Val-Pro-Pro (valine-proline-proline) have been shown to lower blood pressure in animal models and clinical studies. In vitro experiments were performed to elucidate the effects of Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro (leucine-proline-proline) on vascular function. Isolated spontaneously hypertensive rat (SHR) mesenteric arteries were stored in Krebs solution containing 1 mM of tripeptides at +4 °C for 1, 12 or 24 h. Thereafter, arteries were mounted in an organ bath chamber (+37 °C) for vascular reactivity measurements. Endothelium-dependent relaxation was better preserved (P < 0.05) in mesenteric arteries stored with tripeptides versus the control. Endothelium-independent relaxation remained unaltered. Endothelium-derived hyperpolarizing factor (EDHF)-related relaxation was more pronounced in arteries stored with Ile-Pro-Pro. Angiotensin-converting enzyme (ACE)-inhibitory activity of tripeptides was demonstrated after 24 h storage suggesting its role in improved relaxation. Thus, tripeptides do not affect smooth muscle but they protect endothelium in cold storage.     

Reducing postpartum weight retention – a pilot trial in primary health care

Background  

Postpartum weight retention may contribute to the development of obesity. We studied whether individual counselling on diet and physical activity from 2 to 10 months postpartum has positive effects on diet and leisure time physical activity and increases the proportion of primiparas returning to their pre-pregnancy weight.