Nutritional Composition and Therapeutic Potential of Pineapple Peel - A Comprehensive Review.

Pineapple (Ananas comosus), the succulent and vibrant tropical fruit, is a symbol of exoticism and sweetness that captures the hearts and palates of people around the world. The pineapple peel, often considered as waste, has garnered attention for its potential applications. The pineapple peel is rich in essential nutrients, including calcium, potassium, vitamin C, carbohydrates, dietary fiber, and water, making it beneficial for the digestive system, weight management, and overall balanced nutrition. It contains significant amounts of sugars such as sucrose, glucose, and fructose, along with citric acid as the predominant organic acid. The peel also contains bromelain, a proteolytic enzyme known for its digestive properties. Studies have highlighted the pharmacological properties of pineapple peel, such as its potential anti-parasitic effects, alleviation of constipation, and benefits for individuals with irritable bowel syndrome (IBS). Efforts are being made to promote the utilization of pineapple peel as a valuable resource rather than mere waste. Its applications range from the production of vinegar, alcohol, and citric acid to the development of various food products, including squash, syrup, jelly, and pickles. Further research and innovation are required to fully explore the potential of pineapple peel and establish sustainable practices for its utilization, contributing to waste reduction and the development of value-added products.

Structural, chemical and technofunctional properties pectin modification by green and novel intermediate frequency ultrasound procedure.

The impact of intermediate frequency ultrasound (IFUS, 582, 864 and 1144 kHz), mode of operation (continue and pulsed) and ascorbic acid (Aa) addition on the structural, chemical and technofunctional properties of commercial citrus high methoxyl-grade pectin (HMP) was investigated. The chemical dosimetry of IFUS, monitored by the triiodide formation rate (I3-), demonstrated that the pulsed ratio (1900 ms on/100 ms off) at the three frequencies was similar to that of continue mode but IFUS1144 kHz produced more acoustic streaming demonstrated by the height liquid measured using image analysis. In presence of Aa, HMP presented higher fragmentation than in its absence. IFUS did not give rise any changes in the main functional groups of the HMP. In general, a reduction in molecular weight was observed, being the presence of Aa the most influencing factor. Regarding monosaccharides, IFUS modified the structure of homogalacturonan and rhamnogalacturonan-I and increased of GalA contents of the HMP in presence of Aa at the above three frequencies. A reducing of the consistency index (k) and increasing of the flow index (n) of HMP were showed by IFUS frequency and Aa addition. The emulsifying activity and stability index were increased for HMP treated by IFUS in continue mode at all frequencies and in presence of Aa. The results presented in this research shown the effectiveness of IFUS as tool to modify pectin into different structures with different functionalities.

The Chemical Profile, Antioxidant, and Anti-Lipid Droplet Activity of Fluid Extracts from Romanian Cultivars of Haskap Berries, Bitter Cherries, and Red Grape Pomace for the Management of Liver Steatosis.

This study aimed to investigate, for the first time, the chemical composition and antioxidant activity of fluid extracts obtained from three Romanian cultivars of haskap berries (Lonicera caerulea L.) var. Loni, bitter cherries (Prunus avium var. sylvestris Ser.) var. Silva, and pomace from red grapes (Vitis vinifera L.) var. Mamaia, and their capacity to modulate in vitro steatosis, in view of developing novel anti-obesity products. Total phenolic, flavonoid, anthocyanin, and ascorbic acid content of fluid extracts was spectrophotometrically assessed and their free radical scavenging capacity was evaluated using Trolox Equivalent Antioxidant Capacity (TEAC) and free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition assays. The Pearson coefficients showed a moderate correlation between the antioxidant activity of fluid extracts and their phenolic content, but a strong correlation between anthocyanin and ascorbic acid content. HPLC analysis identified and quantified the main phenolic compounds of chlorogenic and syringic acid, catechin, and glycosylated kaempferol, apigenin, and quercetin, in variable proportions. An in vitro experimental model of steatosis was developed in HepG2 hepatocytes treated with a mixture of free fatty acids. Cell culture analyses showed that cytocompatible concentrations of fluid extracts could significantly reduce the lipid accumulation and inhibit the reactive oxygen species, malondialdehyde, and nitric oxide secretion in stressed hepatocytes. In conclusion, these results put an emphasis on the chemical compounds' high antioxidant and liver protection capacity of unstudied fluid extracts obtained from Romanian cultivars of bitter cherries var. Silva and pomace of red grapes var. Mamaia, similar to the fluid extract of haskap berries var. Loni, in particular, the positive modulation of fat deposition next to oxidative stress and the lipid peroxidation process triggered by fatty acids in HepG2 hepatocytes. Consequently, this study indicated that these fluid extracts could be further exploited as hepatoprotective agents in liver steatosis, which provides a basis for the further development of novel extract mixtures with synergistic activity as anti-obesity products.

Fracture resistance and bonding performance after antioxidants pre-treatment in non-vital and bleached teeth.

This study aimed to evaluate the effect of antioxidant solutions on fracture strength and bonding performance in non-vital and bleached (38% hydrogen peroxide) teeth. One hundred and eighty dentin specimens were obtained, 60 for each test: fracture strength, hybrid layer thickness, and bond strength. The groups (n=10) were randomly composed according to post-bleaching protocol: REST - restoration, without bleaching; BL - bleaching + restoration; SA - bleaching, 10% sodium ascorbate solution, and restoration; AT - bleaching, 10% α-tocopherol solution, and restoration; CRAN - bleaching, 5% cranberry solution, and restoration; CAP - bleaching, 0.0025% capsaicin solution, and restoration. Data were analyzed with ANOVA, Kruskal-Wallis, Dunn, and Qui-Square tests (α=0.05). The highest fracture strength values were observed in REST (1508.96 ±148.15 N), without significant difference for the bleached groups (p>0.05), regardless of the antioxidant use. The hybrid layer thickness in the group that was not subjected to bleaching (REST) was significantly higher than in any other group. The bond strength in the bleached and antioxidants-treated groups (SA, AT, CRAN, CAP) has no differences with the bleached group without antioxidants (BL). Adhesive failures were predominant in the groups that did not receive the antioxidant application. In conclusion, the evaluated antioxidants did not show an effect on the fracture strength, hybrid layer thickness, or bond strength of dentin bleached after endodontic treatment. The application of 10% sodium ascorbate, 10% alpha-tocopherol, 5% cranberry, or 0.0025% capsaicin solutions is not an effective step and should not be considered for the restorative protocols after non-vital bleaching.

Sulfur-bridging the gap: investigating the electrochemistry of novel copper chelating agents for Alzheimer's disease applications.

There is currently an unmet demand for multi-functional precision treatments for Alzheimer's disease (AD) after several failed attempts at designing drugs based on the amyloid hypothesis. The focus of this work is to investigate sulfur-bridged quinoline ligands that could potentially be used in chelation therapies for a subpopulation of AD patients presenting with an overload of labile copper ions, which are known to catalyze the production of reactive oxygen species (ROS) and exacerbate other markers of AD progression. The ligands 1-(2'-thiopyridyl)isoquinoline (1TPIQ) and 2-(2'-thiopyridyl)quinoline (2TPQ) were synthesized and characterized before being electrochemically investigated in the presence of different oxidizing and reducing agents in solution with a physiological pH relevant to the brain. The electrochemical response of each compound with copper was studied by employing both hydrogen peroxide (H2O2) as an oxidizing agent and ascorbic acid (AA) as an antioxidant during analysis using cyclic voltammetry (CV). The cyclic voltammograms of each quinoline were compared with similar ligands that contained aromatic N-donor groups but no sulfur groups to provide relative electrochemical properties of each complex in solution. In a dose-dependent manner, it was observed that AA exerted dual-efficacy when combined with these chelating ligands: promoting synergistic metal binding while also scavenging harmful ROS, suggesting AA is an effective adjuvant therapeutic agent. Overall, this study shows how coordination by sulfur-bridged quinoline ligands can alter copper electrochemistry in the presence of AA to limit ROS production in solution.

The effect of ascorbic acid and cranberry on the bond strength, surface roughness, and surface hardness of bleached enamel with hydrogen peroxide and zinc phthalocyanine activated by photodynamic therapy.

AIM: To evaluate the effect of different bleaching methods 40% (hydrogen peroxide) HP and Zinc Phthalocyanine (ZP) activated by photodynamic therapy (PDT) with the utilization of diverse procedures of reversal (10% ascorbic acid and 6% cranberry solution) on bond values, surface microhardness and surface roughness of bleached enamel surface. MATERIAL AND METHODS: An aggregate of 60 extracted human mandibular molars was gathered and the buccal surface of each specimen was exposed to 2 mm of enamel surface for bleaching with chemical and photoactivated agents with the use of reversal solutions. Specimens were divided into six groups (n = 10) at random- Group 1: samples bleached with 40% HP with 10% ascorbic acid (reversal agent), group 2: ZP activated by PDT with 10% ascorbic acid (reversal agent), group 3: 40% HP with 6% cranberry solution as a reversal agent, group 4: ZP activated by PDT with 6% cranberry solution, group 5: 40% HP and group 6: ZP activated by PDT with no reversal agents. Resin cement restoration was performed via etch and rinse technique and SBS was estimated by using the universal testing machine, SMH by using Vickers hardness tester, and Ra by stylus profilometer. Statistical analysis was executed using the ANOVA test and the Tukey multiple tests (p<0.05). RESULTS: Enamel surface bleached with 40% HP reversed with 10% ascorbic acid displayed the highest SBS while 40% HP with no reversal agent use showed the least SBS. For SMH, ZP activated by PDT when applied on the enamel surface and reversed with 10% ascorbic acid showed the highest SMH while when bleached with 40% HP and reversed with 6% cranberry solution showed the least SMH value. For Ra, Group 3: samples bleached with 40% HP with 6% cranberry solution as reversal agent showed the highest Ra value while bleaching of enamel surface with ZP activated by PDT with 6% cranberry displayed the least Ra value. CONCLUSION: Bleached enamel surface with Zinc Phthalocyanine activated by PDT with the application of 10% ascorbic acid as reversal solution has demonstrated the highest SBS and SMH with acceptable surface roughness for bonding adhesive resin to the enamel surface.

Stability of labile xanthones and dihydrochalcones in a ready-to-drink honeybush beverage during storage.

BACKGROUND: The shelf-life of a functional herbal tea-based beverage is important not only for consumer acceptability, but also for the retention of bioactive compounds. The present study aimed to clarify the role of common iced tea beverage ingredients (citric and ascorbic acids) on the shelf-life stability of an herbal tea-based beverage. A hot water extract of green Cyclopia subternata, also used as honeybush tea, was selected as the main ingredient because it provides different types of phenolic compounds associated with bioactive properties (i.e. xanthones, benzophenones, flavanones, flavones and dihydrochalcones). RESULTS: The model solutions were stored for 180 and 90 days at 25 and 40 °C, respectively. Changes in their volatile profiles and color were also quantified as they contribute to product quality. 3',5'-Di-ß-d-glucopyranosyl-3-hydroxyphloretin (HPDG; dihydrochalcone) and, to a lesser extent, mangiferin (xanthone), were the most labile compounds. Both compounds were thus identified as critical quality indicators to determine shelf-life. The stability-enhancing activity of the acids depended on the compound; ascorbic acid and citric acid enhanced the stability of HPDG and mangiferin, respectively. However, when considering all the major phenolic compounds, the base solution without acids was the most stable. This was also observed for the color and major volatile aroma-active compounds [α-terpineol, (E)-ß-damascenone, 1-p-menthen-9-al and trans-ocimenol]. CONCLUSION: The addition of acids, added for stability and taste in ready-to-drink iced tea beverages, could thus have unwanted consequences in that they could accelerate compositional changes and shorten the shelf-life of polyphenol-rich herbal tea beverages. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Understanding the rod-to-tube transformation of self-assembled ascorbyl dipalmitate lipid nanoparticles stabilized with PEGylated lipids.

We previously established a nanoparticle-based drug delivery system (DDS) for high-dose ascorbic acid therapy by self-assembly of a lipid-modified ascorbic acid derivative, L-ascorbyl 2,6-dipalmitate (ASC-DP). The particles' morphology should be modified for effective DDSs. Here, we modulated the morphology of self-assembled ASC-DP nanoparticles using two different PEGylated lipids, distearoylphosphatidylethanolamine-polyethylene glycol (DSPE-PEG) and cholesterol-polyethylene glycol (Chol-PEG), with various PEG molecular weights. At the preparation molar ratio of 10 : 1 (ASC-DP/PEGylated lipid), rod-like nanoparticles emerged in the ASC-DP/DSPE-PEG system, whereas the ASC-DP/Chol-PEG system yielded tube-like nanoparticles. The internal structures of both rod-like ASC-DP/DSPE-PEG and tube-like ASC-DP/Chol-PEG nanoparticles were similar to that of repeated ASC-DP bilayers. The particles' surfaces featured PEGylated lipids, which stabilized the structure and dispersion of the nanoparticles. For both systems, the particle size increased slightly with increasing the PEGylated lipid's PEG molecular weight. Increasing the PEG molecular weight decreased the inner tunnel size of tube-like ASC-DP/Chol-PEG nanoparticles. A mechanism has been proposed for the rod-to-tube transformation. Surface-layer free-energy changes owing to the mixing of multiple lipids and PEG chain repulsion are thought to underlie the inner tunnels' formation. The rod-to-tube morphology of self-assembled ASC-DP nanoparticles can be modulated by controlling the PEGylated lipids' structure, including the lipid species and the PEG chain length.

Ascorbic acid-loaded gliadin nanoparticles as a novel nutraceutical formulation.

Ascorbic acid (AA) is one of the foremost antioxidants. Unfortunately, its sensitivity to different external stimuli such as light, heat and oxygen are concrete limitations for its use. Various approaches have been investigated in order to circumvent this problem and enhance the stability of the active compound, besides promoting its use for different applications. In this investigation, AA was encapsulated in a vegetal protein-based matrix made up of gliadin, the prolamin obtained from wheat kernels, with the aim of proposing a novel nutraceutical formulation. The nanosystems were characterized by an average diameter of < 200 nm and a negative surface charge of âˆ¼ -40 mV. The samples were not destabilized after incubation at different temperatures (up to 70 °C) or after the pasteurization procedure. Suitable stability was also observed in NaCl 100 mM, as well as after cryodesiccation when 10 % w/v of mannose was used. The gliadin nanoparticles showed the ability to retain high amounts of AA, promoting its prolonged release in PBS and under simulated gastrointestinal conditions. The nanosystems enhanced the antioxidant features of the compound as compared to its free form and preserved its chemical stability following UV exposition. The results demonstrate the potential application of the investigated nanoparticles as a novel nutraceutical formulation or as food fortificants.

Iron porphyrin-based porous organic polymer with high peroxidase-like activity as colorimetric sensor for glutathione and ascorbic acid assay.

A new iron porphyrin-based organic polymer (Fe-POP) was synthesized through the William ether reaction. The as-prepared Fe-POP presented high chemical stability, wide pore distribution, high iron content, and strong affinity with 3,3',5,5'-tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2), which contributed to its excellent peroxidase-mimicking performance. In the presence of H2O2, Fe-POP could catalyze the transparent TMB into blue ox-TMB, which could be easily distinguished by the naked eyes. Moreover, glutathione (GSH) and ascorbic acid (AA) could convert blue ox-TMB into colorless TMB due to the inhibitory effect of GSH/AA to the catalytic oxidation of TMB. Based on this phenomenon, a rapid and sensitive colorimetric method for the assay of H2O2, GSH, and AA was developed using Fe-POP as sensor. The detection limits of H2O2, GSH, and AA  were 1.37, 0.44, and 0.33 µM, respectively. Finally, the colorimetric method based on Fe-POP was used to evaluate the GSH and AA content in real samples, which provided the guidance for GSH and AA supplements in our daily diet, suggesting the significant potential of Fe-POP in practical applications.

Mechanism of viscosity reduction of okra pectic polysaccharide by ascorbic acid.

In this work, effects of ascorbic acid (AH2) treatment on the viscosity and structural properties of okra pectic polysaccharide (OPP) and its mechanism were investigated. Results showed that AH2 could decrease the apparent viscosity of OPP, and the reducing ability was promoted by high temperature and the addition of Fe2+, Cu2+ or H2O2. The molecular weight was significantly decreased with increasing AH2 concentration, but it had little effects on the monosaccharide composition, glycosidic linkages, infrared characteristics, and morphology of OPP after AH2 incubation. Hydroxyl radicals were generated during the incubation, which can be activated by introducing Fe2+, Cu2+ or H2O2. In summary, the viscosity reduction of OPP induced by AH2 was related to the formation of hydroxyl radicals. The present study provides some recommendations for the application of OPP in food and other products containing AH2.

Effect of Flavonoids in Hawthorn and Vitamin C Prevents Hypertension in Rats Induced by Heat Exposure.

BACKGROUND: Excessive oxidative stress is associated with hypertension in professional high-temperature working conditions. Polyphenols exhibit a cardioprotective effect. Hawthorn contains high amounts of flavonoids, though its effect on hypertension protection has yet to be studied. This study aims to investigate this effect of extract of hawthorn (EH) or its combination with vitamin C (Vit. C) in rats induced by working under a hot environment. METHODS: Forty-two male rats were randomly divided into a control group under normal temperature and six treatment groups exposed at 33 ± 1 °C along with 1 h of daily treadmill running. They were orally provided with water, Vit. C (14mg/kg), EH (125, 250, and 500 mg/kg), and EH500 + Vit. C, once a day for four weeks. RESULTS: Both EH and Vit. C alone reduced the systolic and diastolic blood pressure of rats exposed to the heat environment; however, their joint supplementation completely maintained their blood pressure to the normal level throughout the experimental period. No morphological changes were found on the intima of aorta. Moreover, the co-supplementation of EH and Vit. C prevented the changes of heat exposure in inducing oxidative stress markers, such as glutathione peroxidase, catalase, total antioxidant capacity, and nitric oxide; the synergistic action was more effective than either individual treatment of EH and Vit. C. Furthermore, the administration of EH had more potent effects on increasing superoxide dismutase, IL-2, the 70 kilodalton heat shock proteins and high sensitivity C reactive protein, and decreasing serum malondialdehyde and lipofuscin in vascular tissue than those in Vit. C group. CONCLUSIONS: A strong synergistic effect of EH and Vit. C on the prevention of hypertension under heat exposure was established, as they inhibited the oxidative stress state. This study also sets up a novel intervention strategy in animal models for investigation on the early phases of hypertension induced by heat exposure.

Ascorbic acid specifically reduces the misclassification of nonirritating reactive chemicals in the OptiSafe™ macromolecular eye irritation test.

Recently, we showed that the addition of physiological concentrations of ascorbic acid, a tear antioxidant, to the OptiSafe™ macromolecular eye irritation test reduced the false-positive (FP) rate for chemicals that had reactive chemistries, leading to the formation of reactive oxygen species (ROS) and molecular crosslinking. The purpose of the current study was to 1) increase the number of chemicals tested to comprehensibly determine whether the antioxidant-associated reduction in OD is specific to FP chemicals associated with ROS chemistries and 2) determine whether the addition of antioxidants interferes with the detection of true positive (TP) and true negative (TN) ocular irritants. We report that when ascorbic acid is added to the test reagents, retesting of FP chemicals with reactive chemistries show significantly reduced OD values (P < 0.05). Importantly, ascorbic acid had no significant effect on the OD values of TP or TN chemicals regardless of chemical reactivity. These findings suggest that supplementation of ascorbic acid in alternative ocular irritation tests may help improve the detection of TN for those commonly misclassified reactive chemicals.

Effect of Ultrasound and Enzymatic Mash Treatment on Bioactive Compounds and Antioxidant Capacity of Black, Red and White Currant Juices.

Ultrasound treatment is recognized as a potential technique for improvement in the nutritional values of fruit juices. This study was initiated with the objective of evaluating bioactive compounds and some important quality parameters of black (BC), red (RC) and white (WC) currant juices obtained from fruit mash preliminarily treated by enzymes combined with ultrasound. Individual and total phenolic content (TPC), anthocyanins, color parameters, ascorbic acid, antioxidant capacity (TEAC), juice yield, pH, titratable acidity, and soluble solids were investigated. Significant increases in the levels of TPC and antioxidant capacity of sonicated samples were observed. However, ultrasound treatment had no effect on individual phenolic compounds of juices. Sonication of mash before juice pressing did not cause any noticeable changes in ascorbic acid content. Only in the case of WC was an increase in content of vitamin C noticed. The color of juices obtained after treatment was similar to the control sample. It was demonstrated that enzymatic combined with ultrasound treatment of mash for different colored currant fruit did not have any dismissive effect and could even improve some parameters of the juice obtained.

Effect of ascorbic acid and citric acid on bioavailability of iron from Tegillarca granosa via an in vitro digestion/Caco-2 cell culture system.

Iron deficiency anaemia (IDA) has been receiving worldwide attention. Developing safe and effective iron supplements is of great significance for IDA treatment. Tegillarca granosa (T. granosa), a traditional aquaculture bivalve species in China, is considered to be an excellent source of micronutrients, but the distribution and bioavailability of these minerals have yet to be investigated. The present research was conducted to determine the contents and in vitro enzymatic digestibility of minerals in T. granosa, using beef and wheat flour as reference foods. Meanwhile, two iron-binding proteins, hemoglobin and ferritin, were extracted from T. granosa, and their structures, iron accessibility and bioavailability were investigated. Moreover, the effects of ascorbic acid (AA) and citric acid (CA), two commonly applied dietary factors, on these parameters were evaluated. Our results indicated that the mineral levels varied significantly among different food matrices, with T. granosa showing the highest contents of the tested elements. Comparison of iron absorption of meat versus wheat flour and hemoglobin versus ferritin confirmed that heme iron exhibited higher bioavailability than non-heme iron. The addition of the two organic acids notably enhanced the cellular iron uptake of T. granosa-derived proteins. This could be because AA/CA weakened hydrogen bonds within proteins and caused disordered secondary structures, thereby improving their enzymatic digestibility and releasing more soluble iron to be available for absorption. The results of this study provided a basis for the development of T. granosa-derived protein-based iron supplements, promoting the diverse utilization of marine aquatic resources.

Relationship between Antioxidant Activity and Ligand Basicity in the Dipicolinate Series of Oxovanadium(IV) and Dioxovanadium(V) Complexes.

Oxidative stress plays an important role in the pathogenesis of many serious diseases, including cancer, atherosclerosis, coronary artery disease, Parkinson's disease, Alzheimer's disease, stroke and myocardial infarction. In the body's natural biochemical processes, harmful free radicals are formed, which can be removed with the help of appropriate enzymes, a balanced diet or the supply of synthetic antioxidant substances such as flavonoids, vitamins or anthocyanins to the body. Due to the growing demand for antioxidant substances, new complex compounds of transition metal ions with potential antioxidant activity are constantly being sought. In this study, four oxovanadium(IV) and dioxovanadium(V) dipicolinate (dipic) complexes with 1,10-phenanthroline (phen), 2,2'-bipyridyl (bipy) and the protonated form of 2-phenylpyridine (2-phephyH): (1) [VO(dipic)(H2O)2]·2 H2O, (2) [VO(dipic)(phen)]·3 H2O, (3) [VO(dipic)(bipy)]·H2O and (4) [VOO(dipic)](2-phepyH)·H2O were synthesized including one new complex, so far unknown and not described in the literature, i.e., [VOO(dipic)](2-phepyH)·H2O. The oxovanadium(IV) dipicolinate complexes with 1,10-phenanthroline and 2,2'-bipyridyl have been characterized by several physicochemical methods: NMR, MALDI-TOF-MS, IR, but new complex [VOO(dipic)](2-phepyH)·H2O has been examined by XRD to confirm its structure. The antioxidant activities of four complexes have been examined by the nitrotetrazolium blue (NBT) method towards superoxide anion. All complexes exhibit high reactivity with superoxide anion and [VOO(dipic)](2-phepyH)·H2O has higher antioxidant activity than L-ascorbic acid. Our studies confirmed that high basicity of the auxiliary ligand increases the reactivity of the complex with the superoxide radical.

Alternative Approach for Specific Tyrosinase Inhibitor Screening: Uncompetitive Inhibition of Tyrosinase by Moringa oleifera.

Tyrosinase (TYR) is a type III copper oxidase present in fungi, plants and animals. The inhibitor of human TYR plays a vital role in pharmaceutical and cosmetic fields by preventing synthesis of melanin in the skin. To search for an effective TYR inhibitor from various plant extracts, a kinetic study of TYR inhibition was performed with mushroom TYR. Among Panax ginseng, Alpinia galanga, Vitis vinifera and Moringa oleifera, the extracts of V. vinifera seed, A. galanga rhizome and M. oleifera leaf reversibly inhibited TYR diphenolase activity with IC50 values of 94.8 ± 0.2 µg/mL, 105.4 ± 0.2 µg/mL and 121.3 ± 0.4 µg/mL, respectively. Under the same conditions, the IC50 values of the representative TYR inhibitors of ascorbic acid and kojic acid were found at 235.7 ± 1.0 and 192.3 ± 0.4 µg/mL, respectively. An inhibition kinetics study demonstrated mixed-type inhibition of TYR diphenolase by A. galanga and V. vinifera, whereas a rare uncompetitive inhibition pattern was found from M. oleifera with an inhibition constant of Kii 73 µg/mL. Phytochemical investigation by HPLC-MS proposed luteolin as a specific TYR diphenolase ES complex inhibitor, which was confirmed by the inhibition kinetics of luteolin. The results clearly showed that studying TYR inhibition kinetics with plant extract mixtures can be utilized for the screening of specific TYR inhibitors.

Production of Margarines Rich in Unsaturated Fatty Acids Using Oxidative-stable Vitamin C-Loaded Oleogel.

Vitamin C (VC)-loaded oleogel (VCOG) with corn oil and monoglyceride stearate was used to replace lipid phase of margarine completely. The oxidative stability of VCOG was evaluated at 60±1°C in a lightproof oven for 18 days and the result showed that VCOG peroxide (> 6 days) and p-anisidine value (> 4 days) was significantly lower than that of bulk oil and VC-free oleogel (p < 0.05). Then, the margarine containing 79.70% VCOG (VCOGM) was in comparison with four commercial butter in sensory and physical characteristic. Results showed that firmness, solid fat content and trans fatty acid of VCOGM were in the lowest values while unsaturated fatty acid and adhesiveness of VCOGM was in the highest values. Furthermore, VCOGM presented the similar springiness, cohesiveness, gumminess, score appearance, texture, taste and overall impression to some/all commercial butters selected in this research (p > 0.05). These results implied that VC-loaded oleogel was an excellent alternative of lipid phase in margarine which confirmed by 55% "definitely buy" and 25% "try once-then decide".

Supplementation with Magnesium Salts-A Strategy to Increase Nutraceutical Value of Pleurotus djamor Fruiting Bodies.

The use of substrates supplemented with minerals is a promising strategy for increasing the nutraceutical value of Pleurotus spp. The current research was performed to analyze the effect of substrate supplementation with magnesium (Mg) salts on the Mg content, biomass, and chemical composition of pink oyster mushroom (Pleurotus djamor) fruiting bodies. Before inoculation, substrate was supplemented with MgCl2 × 6 H2O and MgSO4, both salts were applied at three concentrations: 210, 420, and 4200 mg of Mg per 2 kg of substrate. The harvest period included three flushes. Substrate supplementation with 4200 mg of Mg caused the most significant decrease in mushroom productivity, of about 28% for both Mg salts. The dry matter content in fruiting bodies was significantly lower in the treatment in which 210 mg of Mg was applied as MgSO4 in comparison to the control. Supplementation effectively increased the Mg content in fruiting bodies of P. djamor by 19-85% depending on the treatment, and significantly affected the level of remaining bioelements and anions. One hundred grams of pink oyster fruiting bodies, supplemented with Mg salts, provides more than 20% of the Mg dietary value recommended by the Food and Drug Administration (FDA); thus, supplementation can be an effective technique for producing mushrooms that are rich in dietary Mg. Although P. djamor grown in supplemented substrate showed lower productivity, this was evident only in the fresh weight because the differences in dry weight were negligible. Mg supplementation increased the antioxidant activity of the fruiting bodies, phenolic compounds, and some amino acids, including L-tryptophan, and vitamins (thiamine and l-ascorbic acid).

Photostability of l-tryptophan in aqueous solution: Effect of atmosphere and antioxidants addition.

l-Tryptophan (l-Trp) is an amino acid important in nutrition, and mainly provided by food supplements. However, it is known to be unstable under light irradiation, which is an issue for the nutrition and feed industry. In the present study, the photostability of l-Trp was studied in acidic aqueous solutions under air and under an inert atmosphere, N2. The photodegradation was followed using UV-visible and fluorescence spectroscopy after photolysis. Moreover, molecular orbitals and bond dissociation energies calculations, and electron spin resonance spectroscopy were performed. From all these results, a photodegradation occurring through a free radical pathway was suggested. Interestingly, several antioxidants were tested to improve the photostability of l-Trp, especially during irradiation under air, since the l-Trp was evidenced to be much less stable under air than under N2. The results showed that sodium benzoate or EDTA were not efficient, but antioxidants such as chlorogenic acid, ascorbic acid or potassium sorbate improved significantly the photostability of l-Trp in acidic solutions.