The regulatory role of the tetrapeptide AcSDKP in skin and hair physiology and the prevention of ageing effects in these tissues – a potential cosmetic role

The naturally occurring tetrapeptide acetyl‐N‐Ser‐Asp‐Lys‐Pro (AcSDKP) recognized as a potent angiogenic factor was shown recently to contribute to the repair of cutaneous injuries. In the current article, we report the ability of AcSDKP to exert a beneficial effect on normal healthy skin and scalp and to compensate for the ageing process. In vitro AcSDKP at 10^?11–10^?7 M significantly stimulates the growth of human keratinocytes, fibroblasts and follicle dermal papilla cells. Moreover, it enhances the growth of human epidermal keratinocyte progenitor and stem cells as shown in a clonogenic survival assay. Topical treatment of ex vivo cultured skin explants with 10^?5 M AcSDKP increases the thickness of the epidermis and upregulates the synthesis of keratins 14 and 19, fibronectin, collagen III and IV as well as the glycoaminoglycans (GAGs). In the ex vivo‐cultured hair follicles, AcSDKP promotes hair shaft elongation and induces morphological and molecular modifications matching the criteria of hair growth. Furthermore, AcSDKP at 10^?11–10^?7 M was shown to improve epidermal barrier, stimulating expression of three protein components of tight junctions (claudin‐1, occludin, ZO‐1) playing an important role in connecting neighbouring cells. This tetrapeptide exercises also activation of SIRT1 implicated in the control of cell longevity. Indeed, a two‐fold increase in the synthesis of SIRT1 by cultured keratinocytes was observed in the presence of 10^?11–10^?7 M AcSDKP. In conclusion, these findings provide convincing evidence of the regulatory role of AcSDKP in skin and hair physiology and suggest a cosmetic use of this natural tetrapeptide to prevent skin ageing and hair loss and to promote the cutaneous regeneration and hair growth.     

Scirpusin A,a hydroxystilbene dimer from Xinjiang wine grape,acts as an effective singlet oxygen quencher and DNA damage protector

BACKGROUND: Grapes and red wines are rich sources of phenolic compounds such as anthocyanins, catechins, flavonols and stilbenes, most of which are potent antioxidants showing cardioprotective properties. We first isolated scirpusin A, a hydroxystilbene dimer, from a wine grape of Xinjiang, and studied its antioxidant activity. RESULTS: Reactive oxygen species scavenging effects and the protection against reactive singlet oxygen‐induced DNA damage of scirpusin A have been investigated in our experiments. The concentration of scirpusin A required to inhibit 50% of ¹O₂ generation was 17 µmol L^?1, while addition of scirpusin A at 140 µmol L^?1 caused complete inhibition. Further kinetic study revealed that the reaction of Scirpusin A with singlet oxygen has an extremely high rate constant (k_a = 4.68 × 10⁹ L mol^?1 s^?1). Scirpusin A (140 µmol L^?1) exhibited significant inhibition effects on pBR322 DNA breakage. However, scavenging effects of scirpusin A on superoxide anion O₂^?? and hydroxyl radical ·OH were not potent as the inhibitor rates at a concentration of 1400 µmol L^?1 were 28.83% and 19.5%, respectively. CONCLUSION: The present study shows that scirpusin A is a selective quencher of singlet oxygen and a protector against reactive singlet oxygen‐induced pBR322 DNA damage at very low concentrations. Copyright © 2010 Society of Chemical Industry     

QUENCHING MECHANISMS AND KINETICS OF CAROTENOIDS IN RIBOFLAVIN PHOTOSENSITIZED SINGLET OXYGEN OXIDATION OF VITAMIN D2

The oxidation of vitamin D₂ in a solution of 12% water, 88% acetone and 15 ppm ribqflavin under light or dark was studied by measuring the headspace oxygen. Ribofiavin accelerated the oxidation of vitamin D₂ by singlet oxygen under light, but did not affect vitamin D₂ oxidation under dark. Quenching mechanisms and kinetics within the range of 0–20 ppm β‐cawtene or fucoxanthin and with 0–80 ppm retinyl acetate or retinol on 15 ppm riboflavin photosensitized singlet oxygen oxidation of vitamin D₂ were also studied. The rate of singlet oxygen formation by 15 ppm riboflavin was 1.78 umole oxygen/mL headspace‐hour. The reaction rate constant of vitamin D₂ with singlet oxygen was 2.2 times 10⁷ M^?1A s^?1. The carotenoids minimized the oxidation of vitamin D₂ by quenching singlet oxygen. The total quenching rate constants of retinol, retinyl acetate, jucoxanthin and ft‐carotene were in the order of 1.22 times 10⁸, 5.98 times 10⁸, 1.78 times 10⁹ and 5.00 times 10⁹M^?1. s^?1 respectively, which suggests that as the number of double bonds of carotenoids increases, the quenching rate constant ofcarotenoid increases.     

The revised COLIPA in vitro UVA method

A multicentred study derived from the COLIPA in vitro UVA method was performed to assess the influence of test conditions on UVA protection factor (UVAPF) values in terms of amplitude, reproducibility between laboratories and correlation with in vivo UVA results. Eight products with a range of in vivo UVAPF from three to 29 were used. Two different types of plates, namely high‐roughness (5 μm) and low‐roughness (2 μm) plates, were used with a different application rate for each (1.3 mg cm^?2 and 0.75 mg cm^?2 respectively). The UVR dose applied to both plate types followed the same principle as the original test (1.2 J. cm^?2 × UVAPF0). Strong, significant correlations between in vitro and in vivo UVAPF values were observed for both plate types (Pearson correlation > 0.9, P ≤ 0.01). The correlation and slope obtained with the low‐roughness plates confirmed the previous results obtained by COLIPA. Across all laboratories, higher UVAPF values were obtained on the high‐roughness plates (P < 0.01). Reproducibility of UVAPF values between laboratories was comparable between the two plate roughness values (low roughness, COV = 8%; high roughness, COV = 12%). Considering the in vitro/in vivo comparisons, a regression slope of 0.83 was observed for the low‐roughness plates, in comparison with a value of 1.05 for the high‐roughness plates. The accuracy of the method was improved, therefore, with the use of the high‐roughness plates. With a constraint to recommend the use of only one plate type in the COLIPA UVA in vitro Test, the high‐roughness plate was selected on an on‐going basis to limit variability of results and to provide better accuracy with in vivo data.     

In vitro evaluation of the efficacy of commercial green tea extracts in UV protection

Plants with antioxidant properties are beneficial for preventing the ageing events evoked by UV light, and numerous products based on Camellila sinensis (green tea) are commercially available, many of which claiming to contain bioactive compounds that would prevent UV‐induced skin damage. In this study, we tested the efficacy of five commercial green tea extracts used to enrich cosmetic formulations for protecting human and mouse fibroblasts against UV radiation effects and compared with a fluid one prepared according to the Brazilian Pharmacopoeia recommendations. Taking into consideration that the ageing process can be accelerated by solar radiation by excessive free radical generation, leading to depletion of skin antioxidant defences, and its collapse caused by disruption of the metalloproteinase metabolism, we have used their individual (‐)‐epigallocathechin‐3‐gallate (EGCG) content, the catalase and SOD status and the matrix‐degrading metalloproteases (MMP)‐1, MMP‐9 and MMP‐13 levels as comparative parameters. The EGCG content of the commercial products showed wide variability, ranging from undetectable levels to 58.65 ± 1.12 μg mL^?1, in contrast with the fluid extract (87.82 ± 1.35 μg mL^?1). Moreover, only the pharmacopoeic extract was able to significantly reduce MMP degradation while enhancing the levels of SOD and catalase. These results indicate, for the first time, that the methodologies for preparing herbal mixtures can interfere significantly with compounds endowed with photoprotective effects, and the efficacy of products containing C. sinensis extracts thought to act against effects of solar radiation can be compromised.     

Reducing Campylobacter numbers on chicken carcasses using lactic acid in processing plants

Four trials were carried out at a broiler processing plant to examine the effectiveness of spraying lactic acid solutions for reducing the numbers of Campylobacter on carcasses. The carcasses were naturally contaminated and treated after the inside–outside washer and before the air chiller. Carcasses were treated by spraying in a tunnel or with one of two hand‐held sprayers. Carcasses were treated with a 1.9%, 4% or 8% solution of lactic acid buffered to pH 4 using sodium lactate, and testing was carried out on skin samples from the breast or back/neck. Treating carcasses with 1.9% acid was not effective. Treatments with 4% acid reduced the numbers of Campylobacter on breast skin by 0.4 log₁₀ cfu g^?1 or less and on back/neck skin by 0.8 log₁₀ cfu g^?1. Spraying with an 8% acid solution in the tunnel produced a 1.9‐log cfu g^?1 reduction on breast skin but adversely affected the appearance of the carcasses. Further work is suggested with a 5% solution with consumer testing for acceptability of appearance.     

Effect of ozone and calcium lactate treatments on browning and texture properties of fresh‐cut lettuce

The effects of three treatments, 1 mg L^?1 ozone at 18–20 °C, 15 g L^?1 calcium lactate (CLac) at 50 °C and a combination thereof, were compared on fresh‐cut lettuce over 10 days of refrigerated storage. Respiration rate, browning and texture were examined as main quality indicators. The use of ozone produced a significantly (P < 0.05) higher oxygen decline than the use of CLac (from day 3 to day 10). At the end of storage, CLac (alone or combined with ozone) samples had higher oxygen content (～9%) than ozone samples (～6%). Enzymatic activity decreased significantly (P < 0.05) in ozone samples. Polyphenol oxidase activity in fresh‐cut lettuce treated with ozone (alone or combined with CLac) showed lower values on day 1 (<2500 units g^?1) and at the end of storage (<3000 units g^?1) than CLac samples (4000–4800 units g^?1). Ozone also reduced peroxidase activity to ～300 units g^?1 after treatment. Finally, pectin methylesterase activity was also reduced with ozone, showing a negative effect on textural properties. Data suggested that CLac maintained quality markers better than treatments with ozone and ozone/CLac combination over 10 days of storage. Copyright © 2006 Society of Chemical Industry     

Kinetic Study of the Quenching Reaction of Singlet Oxygen by Common Synthetic Antioxidants (tert-Butylhydroxyanisol, tert-di-Butylhydroxytoluene, and tert-Butylhydroquinone) as Compared with α-Tocopherol

ABSTRACT: Effects of synthetic phenolic antioxidants (BHA, BHT, and TBHQ) on the methylene blue (MB) sensitized photooxidation of linoleic acid as compared with that of α‐tocopherol have been studied. Their antioxidative mechanism was studied by both ESR spectroscopy in a 2,2,6,6‐tetramethylpiperidone (TMPD)‐methylene blue (MB) system and spectroscopic analysis of rubrene oxidation induced by a chemical source of singlet oxygen. Total singlet oxygen quenching rate constants (k_ox?Q+k_q) were determined using a steady state kinetic equation. TBHQ showed the strongest protective activity against the MB sensitized photooxidation of linoleic acid, followed by BHA and BHT. TBHQ (1 × 10^?3 M) exhibited 86.5% and 71.4% inhibition of peroxide and conjugated diene formations, respectively, in linoleic acid photooxidation after 60‐min light illumination. The protective activity of TBHQ against the photosensitized oxidation of linoleic acid was almost comparable to that of α‐tocopherol. The data obtained from ESR and rubrene oxidation studies clearly showed the strong singlet oxygen quenching ability of TBHQ. The k_ox?Q+k_q of BHA, BHT, and TBHQ were determined to be 3.37 × 10⁷, 4.26 × 10⁶, and 1.67 × 10⁸ M^?1 s^?1, respectively. The k_ox?Q+k_q of TBHQ was within the same order of magnitude of that of α‐tocopherol, a known efficient singlet oxygen quencher. There was a high negative correlation (r² = ?0.991) between log (k_ox?Q+k_q) and reported oxidation potentials for the synthetic antioxidants, indicating their charge‐transfer mechanism for singlet oxygen quenching. This is the 1st report on the kinetic study on k_ox?Q+k_q of TBHQ in methanol as compared with other commonly used commercial synthetic antioxidants and α‐tocopherol.     

Effect of feeding intact brown seaweed Ascophyllum nodosum on some digestive parameters and on iodine content in edible tissues in pigs

BACKGROUND: Limited research suggests that brown seaweed (extracts) may be used in pig nutrition for improving gut health and performances and for iodine enrichment of tissues. One in vitro and two in vivo experiments with dried iodine‐rich intact marine seaweed (Ascophyllum nodosum) have been conducted with weaned piglets to further unravel the mechanisms. RESULTS: In vitro investigations revealed a statistically significant depressive effect of seaweed on pig gut flora, especially on Escherichia coli. In vivo, seaweed (10 g kg^?1) had a reducing effect on the E. coli load in the stomach (P = 0.07) and small intestine (P < 0.05), while the lactobacilli/E. coli ratio was enhanced (P < 0.05) in the small intestine, indicating a beneficial shift in the microbial population. Statistically significant increases (P < 0.001) in iodine content were noted for several tissues in piglets on seaweed (20 g kg^?1, corresponding to 10 mg iodine kg^?1 feed) compared with the control diet (1 mg iodine kg^?1 feed). CONCLUSION: Intact A. nodosum brown seaweed may be introduced in pig nutrition as a feed material with a double strategy: improvement of pig gut health and performances and iodine enrichment of porcine tissues. This feeding strategy may alleviate, but not solve, the actual iodine deficiency in Belgium. Copyright © 2009 Society of Chemical Industry     

Direct Spectroscopic Observation of Singlet Oxygen Quenching and Kinetic Studies of Physical and Chemical Singlet Oxygen Quenching Rate Constants of Synthetic Antioxidants (BHA,BHT, and TBHQ) in Methanol

Abstract: Singlet oxygen quenching by synthetic antioxidants (BHA, BHT, and TBHQ) was directly observed by spectroscopic monitoring of luminescence at 1268 nm. The luminescence data showed unambiguous evidence of singlet oxygen quenching by synthetic phenolic antioxidants with the highest activity for TBHQ, followed by BHA and BHT. The protective activities of these synthetic antioxidants on α-terpinene oxidation with chemically-induced singlet oxygen under dark further confirmed their singlet oxygen quenching abilities. Total singlet oxygen quenching rate constants (k_r + k_q) of BHA, BHT, and TBHQ were determined in a system containing α-terpinene (as a singlet oxygen trap) and methylene blue (as a sensitizer) during light irradiation, and the values were 5.14 × 10⁷, 3.41 × 10⁶, and 1.99 × 10⁸ M⁻¹s⁻¹, respectively. After the k_r value of α-terpinene was first determined, the k_r values of the synthetic antioxidants were calculated by measuring their relative reaction rates with singlet oxygen to that of α-terpinene under the identical conditions. The k_r values of the BHA, BHT, and TBHQ were 3.90 × 10⁵, 1.23 × 10⁵, and 2.93 × 10⁶, M⁻¹s⁻¹. The percent partition of chemical quenching over total singlet oxygen quenching (k_r × 100)/(k_r + k_q) for BHA, BHT, and TBHQ were 0.76%, 3.61%, and 1.47%, respectively. The results showed that the synthetic antioxidants quench singlet oxygen almost exclusively through the mechanism of physical quenching. This represents the first report on the singlet oxygen quenching mechanism of these synthetic antioxidants. Practical Application: The synthetic antioxidants, especially TBHQ, have been found to have a strong singlet oxygen quenching ability. This article also clearly showed that singlet oxygen quenching by synthetic antioxidants was mainly by the physical quenching mechanism. The results suggested that these synthetic antioxidants, especially TBHQ, could be used practically for the protection of the food components such as edible oils and vitamins against singlet oxygen induced oxidations without significant losses of antioxidant activity during storage under light.     

Different concentrations of grape seed extract affect in vitro starch fermentation by porcine small and large intestinal inocula

BACKGROUND: Grape seed extract (GSE) phenolics have potential health‐promoting properties, either from compounds present within the extract, or metabolites resulting from gastrointestinal tract (GIT) fermentation of these compounds. This study describes how GSE affected the kinetics and end‐products of starch fermentation in vitro using pig intestinal and fecal inocula. Six GSE concentrations (0, 60, 125, 250, 500, and 750 µg ml^?1 were fermented in vitro by porcine ileal and fecal microbiota using starch as the energy source. Cumulative gas production, and end‐point short chain fatty acids and ammonia were measured. RESULTS: GSE phenolics altered the pattern (gas kinetics, and end‐products such as SCFA and NH ) of starch fermentation by both inocula, at concentrations above 250 µg ml^?1. Below this level, neither inoculum showed any significant (P > 0.05) effect of the GSE. CONCLUSION: The results show that GSE phenolics at a concentration over 250 µg ml^?1 can have measurable effects on microbial activity in an in vitro fermentation system, as evidenced by the changes in kinetics and end‐products from starch fermentation. This suggests that fermentation patterns could be conceivably shifted in the actual GIT, though further evidence will be required from in vivo studies. Copyright © 2012 Society of Chemical Industry     

Characterization of Brazilian lager and brown ale beers based on color, phenolic compounds, and antioxidant activity using chemometrics

BACKGROUND: Epidemiological studies have shown that beer has positive effects on inhibiting atherosclerosis, decreasing the content of serum low‐density lipoprotein cholesterol and triglycerides, by acting as in vivo free radical scavenger. In this research, the antioxidant activity of commercial Brazilian beers (n = 29) was determined by the oxygen radical absorbance capacity (ORAC) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH^·) assays and results were analyzed by chemometrics. RESULTS: The brown ale samples (n = 11) presented higher (P < 0.05) flavonoids (124.01 mg L^?1), total phenolics (362.22 mg L^?1), non‐flavonoid phenolics (238.21 mg L^?1), lightness (69.48), redness (35.75), yellowness (55.71), color intensity (66.86), hue angle (59.14), color saturation (0.9620), DPPH^· values (30.96% inhibition), and ORAC values (3, 659.36 µmol Trolox equivalents L^?1), compared to lager samples (n = 18). Brown ale beers presented higher antioxidant properties (P < 0.05) measured by ORAC (1.93 times higher) and DPPH (1.65 times higher) compared to lager beer. ORAC values correlated well with the content of flavonoids (r = 0.47; P = 0.01), total phenolic compounds (r = 0.44; P < 0.01) and DPPH (r = 0.67; P < 0.01). DPPH values also correlated well to the content of flavonoids (r = 0.69; P < 0.01), total phenolic compounds (r = 0.60; P < 0.01), and non‐flavonoid compounds (r = 0.46; P = 0.01). CONCLUSION The results suggest that brown ale beers, and less significantly lager beers, could be sources of bioactive compounds with suitable free radical scavenging properties. Copyright © 2010 Society of Chemical Industry     

The prevalence and some metabolic traits of Brochothrix thermosphacta in meat and meat products packaged in different ways

BACKGROUND: The effect of Brochothrix thermosphacta on the quality of meat and meat products is of vital importance in connection with Regulation EC/178/2002 extending the definition of unsafe foodstuffs to encompass all those which are unfit for human consumption. This study aimed to determine the prevalence of B. thermosphacta in meat and meat products packaged under different conditions and to estimate the effect of B. thermosphacta strains on product quality based on their protein and lipid degradation activity. RESULTS: B. thermosphacta was absent in only two of 132 samples. All other samples were contaminated with this bacterium (10¹ to 10⁹cfu g^?1 meat and 10² to 10⁸cfu g^?1meat product). In products stored under high‐oxygen atmosphere Brochothrix cells accounted for almost 100% total mesophilic count (TMC) and below 50% TMC in oxygen‐free atmosphere. While the tested B. thermosphacta strains did not show any proteolytic activity, most of them displayed lipolytic activity at 25 °C and some even at 4 °C. CONCLUSION: B. thermosphacta is commonly present in meat and meat products packaged in different ways. This bacterium can display lipolytic activity also at refrigeration temperature. Its over‐proliferation can be inhibited through vacuum packaging or packaging under a modified atmosphere with reduced oxygen content. Copyright © 2011 Society of Chemical Industry     

Isolation and characterization of collagen from bigeye snapper (Priacanthus macracanthus) skin

Acid‐solubilized collagen (ASC) and pepsin‐solubilized collagen (PSC) were isolated from the skin of bigeye snapper (Priacanthus macracanthus) with yields of 64 and 11 g kg^?1 wet weight, respectively. Both ASC and PSC were characterized as type I collagens with no disulfide bonds. Peptide maps of ASC and PSC digested by V8 protease and lysyl endopeptidase showed some differences in peptide patterns and were totally different from those of calf skin collagen. The maximum solubility was observed at pH 4 and 5 for ASC and PSC, respectively. A sharp decrease in solubility of both collagens in acetic acid was found with NaCl concentration above 30 g l^?1. Thermal transitions of ASC and PSC in deionized water were observed with T_max of 30.37 and 30.87 °C, respectively, and were lowered in the presence of acetic acid (0.05 mol kg^?1 solution). Therefore, ASC was a major fraction in bigeye snapper skin and it exhibited some different characteristics to PSC. Copyright © 2005 Society of Chemical Industry     

Expression of unique chimeric human papilloma virus type 16 (HPV‐16) L1‐L2 proteins in Pichia pastoris and Hansenula polymorpha

Cervical cancer is ranked the fourth most common cancer in women worldwide. Despite two prophylactic vaccines being commercially available, they are unaffordable for most women in developing countries. We compared the optimized expression of monomers of the unique HPV type 16 L1‐L2 chimeric protein (SAF) in two yeast strains of Pichia pastoris, KM71 (Mut^s) and GS115 (Mut⁺), with Hansenula polymorpha NCYC 495 to determine the preferred host in bioreactors. SAF was uniquely created by replacing the h4 helix of the HPV‐16 capsid L1 protein with an L2 peptide. Two different feeding strategies in fed‐batch cultures of P. pastoris Mut^s were evaluated: a predetermined feed rate vs. feeding based on the oxygen consumption by maintaining constant dissolved oxygen levels (DO stat). All cultures showed a significant increase in biomass when methanol was fed using the DO stat method. In P. pastoris the SAF concentrations were higher in the Mut^s strains than in the Mut⁺ strains. However, H. polymorpha produced the highest level of SAF at 132.10 mg L^?1 culture while P. pastoris Mut^s only produced 23.61 mg L^?1. H. polymorpha showed greater potential for the expression of HPV‐16 L1/L2 chimeric proteins despite the track record of P. pastoris as a high‐level producer of heterologous proteins.     

Surface rejuvenating effect of Achillea millefolium extract

Proopiomelanocortin is a precursor peptide that gives rise to several neuropeptides including adrenocorticotrophic hormone (ACTH) and β‐endorphin. POMC‐derived peptides have been shown to be synthesized in human epidermis where they modulate numerous skin functions. Because we previously observed that melanocortin receptor‐2 and μ‐opioid receptor 1, the respective receptors for ACTH and β‐endorphin decreased with ageing in human epidermis, we have selected an active ingredient (INCI name: Achillea millefolium extract) able to upregulate receptor expressions. The aim of the present work was first to evaluate the effect of A. millefolium extract on the expression pattern of various epidermal differentiation markers ex vivo in normal human skin biopsies using quantitative image analysis and second to evaluate its capacity to rejuvenate the appearance of skin surface in vivo. Results show an improved expression profile of cytokeratin 10, transglutaminase‐1 and filaggrin in cultured skin biopsies as well as an increased epidermal thickness. In vivo, a 2‐month treatment with A. millefolium extract at 2% significantly improved the appearance of wrinkles and pores compared with placebo. Results were also directionally better than those of glycolic acid that was chosen as reference resurfacing molecule.     

Ochratoxin A in wines,musts and grape juices from Spain

A survey on the occurrence of ochratoxin A (OTA) in 240 grape‐based beverages was carried out. Red and white wines from four different Spanish Designations of Origin (n = 160), musts (n = 20), grape juices (n = 10), ordinary wines (n = 20), special wines (Malaga, muscatel, sherry, vermouth, etc) (n = 20) and sparkling wines (n = 10) were assayed for OTA content using immunoaffinity column clean‐up and high‐performance liquid chromatography with fluorimetric detection (detection limit 0.05 µg l^?1). Forty‐three (17.9%) of the samples tested contained detectable levels of OTA. The overall mean OTA concentration in red and white wines of Designations of Origin was 0.30 and 0.18 µg l^?1 respectively (ranges 0.05–3.19 and 0.05–1.13 µg l^?1 respectively). The percentage of wine samples with detectable amounts of OTA was higher for red (18.3%) than for white (10%) wines. OTA was also found in two of 10 red ordinary wines (0.68 and 4.24 µg l^?1), whereas none of 10 white ordinary wines contained OTA. The mean OTA amount detected in sparkling wines was 0.44 µg l^?1 (range 0.14–0.71 µg l^?1). Two of 20 must samples contained OTA at low levels (0.08 and 0.18 µg l^?1), while none of 10 grape juice samples contained OTA. Highest amounts of OTA were found in special wines (45%), with a maximum of 15.25 µg l^?1 in a muscatel sample. Copyright © 2004 Society of Chemical Industry     

Highly sensitive spectrometric method for determination of hydroquinone in skin lightening creams: application in cosmetics

A highly sensitive, simpler, faster and economical UV/visible spectrophotometric method has been established for the estimation of hydroquinone (HQ) in dilute organic matrices. The method is based on using ammonium meta‐vanadate as an oxidizing catalyst for conversion of HQ to p‐benzoquinone (BQ) in the presence of oxygen. As a result of higher absorption of UV light by BQ than by HQ, its signal has been utilized for determining HQ at the trace level. The effect of various parameters such as amount of oxidizing agent, stability time, temperature, acids and bases, solvents and interference by various compounds has been studied upon the absorption of BQ as HQ. Under optimized conditions, Beer’s Law was obeyed in the range of 0.025–2.00 μg ml^?1 HQ at 245.5 nm using 1 : 1 (V/V) 2‐propanol/water system with a lower detection limit of 7 ng ml^?1 and linear regression coefficient of 0.9998. Relative standard deviation of 1.5% was observed for 0.5 μg ml^?1 HQ solution (n = 11). The newly developed method has been successfully applied to diluted samples of various skin lightening creams for free HQ determination at the trace level. Comparison of the results obtained by the proposed method with those by a previously reported method proved its validity.     

Transforming sugars into fat – lipid biosynthesis using different sugars in Yarrowia lipolytica

In an era of ever‐increasing energy demands, a promising technology is being developed: the use of oleaginous microorganisms such as Yarrowia lipolytica to convert waste materials into biofuels. Here, we constructed two Y. lipolytica strains that displayed both increased lipid accumulation and more efficient use of biomass‐derived sugars, including glucose, fructose, galactose and inulin. The first strain, Y. lipolytica YLZ150, was derived from the French wild‐type strain W29. It had inhibited triacylglycerol mobilization (?tgl4 ) and β‐oxidation (?pox1–6 ), and it overexpressed GPD1 , DGA2 , HXK1 , the native Leloir pathway, SUC2 from Saccharomyces cerevisiae and INU1 from Kluyveromyces marxianus . The second strain, Y. lipolytica Y4779, was derived from the Polish A‐101 strain. It had inhibited β‐oxidation (?mfe2 ) and overexpressed GPD1 , DGA1 , HXK1 , YHT3, SUC2 and INU1 . In the first experiment, strain YLZ150 was batch‐cultured in media containing different hexoses; the highest values for lipid concentration and yield of lipids from the substrate were obtained using fructose (20.3 g dm^?3 and 0.14 g g^?1, respectively). In the second experiment, we grew the two strains in fed‐batch cultures to examine lipid biosynthesis from inulin (a fructose polymer). For Y4779, the lipid concentration was 10.3 g dm^?3 and the yield of lipids from substrate was 0.07 g g^?1; in contrast, for YLZ150, these values were 24 g dm^?3 and 0.16 g g^?1, respectively. The YLZ150 strain is thus able to efficiently exploit glucose, fructose, galactose, sucrose and inulin for lipid biosynthesis. Copyright © 2017 John Wiley & Sons, Ltd.     

Injection of marinade with actinidin increases tenderness of porcine M. biceps femoris and affects myofibrils and connective tissue

BACKGROUND: Marination of beef muscles with brine solutions containing proteolytic enzymes from fruit extracts has been shown to tenderize meat. However, the effect of marination with actinidin on tenderness of pork muscles has not been investigated. Tenderness and eating quality of porcine M. biceps femoris was investigated by Warner–Bratzler (WB) shear test and sensory evaluation after injection of brine containing up to 11 g L^?1 actinidin‐containing kiwi fruit powder and 2, 5 or 9 days of storage. RESULTS: Actinidin decreased WB shear force, increased tenderness and did not affect flavour and juiciness. Injection of 2.8 g L^?1 actinidin powder and storage for 2 days resulted in WB shear force values similar to control samples stored for 5 or 9 days. In samples injected with 10 g L^?1 actinidin powder, degradation of desmin and percentage of heat‐soluble collagen (P < 0.05) increased compared to control samples. Myofibrillar particle size tended to decrease (P < 0.1) with increasing actinidin concentration. No major changes were observed by proteome analysis. Atomic force microscopy showed actinidin‐induced damage of endomysium surrounding isolated single muscle fibres. CONCLUSION: Our results indicate that actinidin tenderizes pork M. biceps femoris by affecting both the myofibrils and connective tissue. Copyright © 2009 Society of Chemical Industry