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Synthesis of highly fluorescent carbon dots from lemon and onion juices for determination of riboflavin in multivitamin/mineral supplements

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Journal of Pharmaceutical Analysis 2019年第3期9卷 209-216页

作者： Severino S. Monte-Filho Stefani I.E. Andrade Marcelo B. Lima Mario C.U. Araujo Universidade Federal da Paraíba CCEN Departamento de Química P.O. Box 5093 Zip Code 58051-970 Joao Pessoa PB Brazil Universidade Federal Rural de Pernambuco-Unidade Acad^emica de Serra Talhada UAST Zip Code 56909-535 Serra Talhada PE Brazil

In this work, lemon and onion biomasses commonly found in street markets are for the first time used to develop a facile, fast and low-cost one-step microwave-assisted carbonization method for synthesis of highly fluorescent carbon dots (CDs). The structure and optical properties of CDs were investigated by TEM, XRD, XRF, UV-Vis, FTIR, and fluorescence spectroscopy. CDs displayed satisfactory optical pro-prieties, a high quantum yield of 23.6%, and excellent water solubility, and the particle size was 4.23-8.22 nm with an average diameter of 6.15 nm. An efficient fluorescent resonance energy transfer (FRET) between the CDs and riboflavin was achieved with CDs acting as donor and riboflavin as acceptor. A linear relationship between FRET and the riboflavin concentration from 0.10 to 3.0 μg/mL was observed, allowing the development of an accurate and fast analytical method to determine this vitamin in multivitamin/mineral supplements. Despite the potential interferences in these supplements, CDs were selective for riboflavin under optimized conditions. A paired t-test at a 95% confidence level indicated no statistically significant difference between the proposed and the reference methods. Recovery test presented values ranged from 96.0% to 101.4%. The limit of detection and relative standard deviation were estimated at 1.0 ng/mL and <2.6% (n = 3), respectively. CDs were successfully synthesized in a domestic microwave oven (1450 W, 6 min), presenting satisfactory parameters when compared with results of other studies reported in the literature, suggesting that the proposed method is a potentially useful method for the synthesis of CDs and determination of riboflavin.

关键词： Carbon dots Microwave-assisted carbonization Lemon-onion juice Riboflavin Multivitamin/mineral supplements Fluorescence

Physicochemical and Microbiological Properties of Bissap (Hibiscus sabdariffa) and Ginger (Zingiber officinale (L) Rose) juices Sold in the Western Part of Abidjan (Côte d’Ivoire)

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Open Journal of Applied Sciences 2022年第6期12卷 964-976页

作者： Gnamien Marcel Ahon Gbouhoury Eric-Kévin Bolou Mamadou Fofana Kouakou Ernest Amoikon National Pedagogical Institute for Technical and Professional Education (NPTPE) Abidjan C&ocirc te d’Ivoire Biology and Health Laboratory UFR Biosciences University Félix HOUPHOU&Euml T-BOIGNY Abidjan C&ocirc te d’Ivoire National Floristic Center UFR Biosciences University Félix HOUPHOU&Euml T-BOIGNY Abidjan C&ocirc te d’Ivoire

juices made from the calyx of Hibiscus sabdariffa (Malvaceae), commonly called Bissap, and the rhizome of Zingiber officinale (Zingiberaceae), known as Gnamankoudji, are widely consumed in Côte d'Ivoire. The artisanal preparation of these juices often makes their quality problematic. The aim of this study is to determine some physicochemical and microbiological properties of these drinks sold in the city of Abidjan. To do this, samples of Bissap and Gnamankoudji juices were collected near schools in the Mamie Adjoua (Yopougon) and Abobodoumé (Attécoubé) districts. Physico-chemical and microbiological analyses were performed on these collected samples. The results show that the Bissap and Gnamankoudji juices have an acid pH (2.47 and 3.71), a low protein content (0.78% and 2.11%) and a high water content (80.13% and 85.21%), respectively. The reducing sugar content ranged from 1.20% to 3.34%, with high total sugar (695 mg/mL and 812 mg/mL), low ash (0.70 ± 0.07;0.91 ± 0.01). On the other hand, these juices contain variable concentrations of minerals from one site to another (magnesium, calcium, phosphorus, potassium and iron). Potassium is the most abundant mineral element, followed by phosphorus and magnesium. Moreover, it is observed that the Gnamankoudji juices contain vitamin C (4.67 to 5.58 mg/100mL), contrary to the Bissap juice. The microbiological analysis indicates the presence of aerobic mesophilic germs (AMG) but a total absence of pathogenic germs in all juices. The important presence of nutrients and the total absence of pathogenic germs in these drinks justify their regular consumption by the population.

关键词： juice Hibiscus sabdariffa Zingiber officinale Chemical Composition Microbiology

磁性纳米粒子负载木瓜蛋白酶的制备、表征及用于果汁澄清(英文)

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催化学报 2013年第10期34卷 1897-1904页

作者： Leila Mosafa Majid Moghadam Mohammad Shahedi Department of Food Science College of AgricultureIsfahan University of Technology Department of Chemistry Catalysis DivisionUniversity of Isfahan

The preparation,characterization,and application of silica-coated magnetic nanoparticles for papain immobilization is *** was covalently attached onto the(3-chloropropyl) trimethoxysilane-modified silica-coated magnetic nanoparticles. The enzyme-immobilized nanoparticles were characterized by Fourier transform infrared spectroscopy,X-ray powder diffraction,scanning electron microscopy,and vibrating sample magnetometry *** surface methodology combined with statistical analyses using Minitab were employed to evaluate optimum operating conditions to immobilize papain on the magnetic *** optimum conditions were: temperature = 27.3℃,pH of the enzyme solution = 7.1,concentration of papain = 3.3 mg/mL,and immobilization time = 10 *** with the free papain,the immobilized papain displayed enhanced enzyme activity,better tolerance to variations in the medium pH and temperature,improved storage stability,and good *** the free and immobilized enzymes were effective for the clarification of pomegranate juice.

关键词： Magnetic nanoparticle Papain Immobilization juice clarification Enzyme activity

Survival and Growth Characteristics of Escherichia coli O157:H7 in Pomegranate-Carrot and Pomegranate-Apple Blend juices

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Food and Nutrition Sciences 2011年第8期2卷 844-851页

作者： Salam A. Ibrahim Tarik Bor Danfeng Song Mehrdad Tajkarimi 不详

Unpasteurized fruit juice has been implicated in outbreaks of Escherichia coli O157:H7 (E. coli O157:H7). Meanwhile, certain fruit, such as pomegranate, contains antimicrobial components. The objective of this study was to investigate the survival and growth characteristics of E. coli O157:H7 on pomegranate juice in laboratory medium and in pomegranate-carrot and pomegranate-apple blend juices at different concentrations. Single strain of E. coli O157:H7 (E0019, H1730, and Cider) was inoculated into brain heart infusion (BHI) broth or a mixture of three strains was inoculated into the blended juices containing pomegranate juice. Our results showed that the addition of pomegranate juice inhibited the growth of tested E. coli O157:H7 in both laboratory medium and blended *** antimicrobial activity increased with increased concentrations of pomegranate juice (P juice blend samples in the presence of 20% and 40% Pomegranate juice respectively. Sensory evaluations performed using a 9 point hedonic scale showed significant satisfaction on using 40% pomegranate juice blend with carrot and apple juices. Our study suggests that pomegranate juice could be used as a natural antimicrobial in different food systems including juices to inhibit the growth of E. coli O157:H7.

关键词： Escherichia Coli O157:H7 Pomegranate juice Antimicrobial Activity

Anti-HelicobacterActivity of Certain Food Plant Extracts and juices and Their Composition in Vitro

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Food and Nutrition Sciences 2011年第8期2卷 868-877页

作者： Anna Babarikina Vizma Nikolajeva Dmitry Babarykin 不详

Plant material screening was performed to study anti-Helicobacter pylori activity in vitro using an agar diffusion method on Columbia blood agar. 33 substances, juices and plant extracts and 35 of their combinations were tested. Quince (Cydonia oblonga) juice demonstrated the strongest anti-H. pylori activity followed by cranberry juice. Con-centrated apple juice, plum, red currant, black chokeberry, raspberry and bilberry juice also showed significant activity. Green tea and apple pomace extract as well as sweet flag rhizome, ginger and wild bergamot extract, cherry syrup, red beet juice and whey did not exhibit anti-Helicobacter activity. Quince juice in combination with bilberry, black chokeberry, red currant juice, green tea, sweet flag rhizome or apple pomace extract as well as cranberry juice in combination with sweet flag rhizome extract demonstrated a synergistic effect on inhibition of H. pylori. The obtained results offer new perspectives for development of functional anti-Helicobacter food product(s) for dietary management of H. pylori infection. The essential components of these products could be the most active juices and extracts like quince and cranberry juice supplemented with a corresponding synergist. Further studies are required to investigate the mechanism of antibacterial action of plant products and their efficacy in vivo.

关键词： Helicobacter Antimicrobial Activity Plant extract juice

Quality Control of juices Produced in Democratic Republic of Congo and Marketed in Lubumbashi

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Food and Nutrition Sciences 2020年第4期11卷 255-261页

作者： Isabelle Kasongo Omba Criss Koba Mjumbe Guyslain Mashini Ngongo Oscar Luboya Numbi Department of Public Health Faculty of Medicine University of Lubumbashi Lubumbashi Democratic Republic of the Congo Microbiology Laboratory Congolese Office of Control COC Lubumbashi City Democratic Republic of Congo

The consumption of juice has increased sharply in recent years in Lubumbashi. The objective of this study was to determine the standards applicable to the types of juice for domestic consumption in Lubumbashi. A descriptive cross-sectional study on quality control (QC) of ten brands of juice selected from around thirty listed on the Lubumbashi markets focused on the determination of different physico-chemical and microbiological parameters. Physical analysis of the juices was carried out in the laboratory of the Congolese Office of Control (OCC) in February 2019. It appears that five samples, or 25%, have a density lower than the ISO 9001 standard. All the samples have a Brix Degree in accordance with French standards applicable by the Congolese control office. The chemical analysis shows that 4 samples, or 20%, have a pH 4, therefore higher than the prescribed standards. As for the titratable acidity and the formaldehyde index, all the samples have values within normal limits. On the other hand, the glucose level of all the samples is abnormally high (≥40 g/L). The sucrose level of 50% of the samples is normal (≥80 g/L). Microbiological analysis revealed that certain juices were without preservatives and harbored aerobic mesophilic germs (10%), lactic bacteria (20%) yeasts and molds (10%). It is urgent that the public authorities bring all the producers to respect the standards in order to protect the health of the populations.

关键词： Fruit juice Quality Control Lubumbashi/Democratic Republic of Congo

Relationships between Fruit Acceptability and Health-Case of Seven Pomegranate (Punica granatumL.) juices

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Food and Nutrition Sciences 2013年第8期4卷 119-130页

作者： Chiraz El Kar Narjes Mtimet Ali Ferchichi Jalloul Bouajila Laboratoire d’Aridoculture et de Cultures Oasiennes Institut des Régions Arides Médenine Tunisie Université de Toulouse Laboratoire des Interactions Moléculaires et Réactivité Chimique et Photochimique UMR CNRS 5623 Université Paul-Sabatier Toulouse France.

The objective of this study was to evaluate acceptability and instrumental measurements (titratable acidity, total soluble sugar, total phenolic, flavonoids, anthocyanins, and condensed tannin contents as well as antioxidant capacity) of seven Tunisian pomegranate cultivars to relate fruit acceptability and beneficial health. Seventy one participants were asked to complete a questionnaire and to indicate their level of acceptance, on a nine point-hedonic scale, for fruit size, sweetness, bitterness, juice color and juice overall acceptability. Taste and aril color were the main criteria to select Pomegranate. Significant differences occurred for all the acceptability tests. Titratable acidity determines the taste and important inter-specific variability in the phenolic contents as well as for the antioxidant capacities was noticed. Anthocyanin and condensed tannin were contributing to the organoleptic properties while bitterness acceptability was negatively correlated to the antioxidant capacity. Also, a relationship was found between the fruit size acceptability and the antioxidant capacity.

关键词： Pomegranate juice Acceptability Tests Instrumental Measurements Phenolic Contents Antioxidant Capacity

Analysis of Certain Fruit juices Using Microwave Techniques

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Journal of Electromagnetic Analysis and Applications 2017年第9期9卷 123-134页

作者： Anil Lonappan Thomas Joachim Odhiambo Afullo Williams Mark Uren Daniels Department of Electrical Engineering Mangosuthu University of Technology Jacobs Durban South Africa School of Electrical Electronic and Computer Engineering Howard College University of KwaZulu-Natal Durban South Africa College of Health Sciences School of Laboratory Medicine and Medical Sciences University of KwaZulu-Natal Durban South Africa

This paper discusses a novel method of analyzing the dielectric properties of juices at various frequencies of microwave band. The measurements were performed using a rectangular cavity with the perturbation technique at the S-band of microwave frequency with fresh juices made instantly from the fruits as well as collected from the packed fruit juices available in the market with the normal added preservatives in order to keep the increase of the shelf life. From the results, it is observed in the certain dielectric properties, the fresh juices samples and packed juices samples were varying and also varying over a period of time. This measurement method is simple and quick and can be used over a range of juices. These results prove a new method of determining the quality control of juices using microwave principles.

关键词： Fruit juice Cavity Perturbation Shelf Life Quality Control

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稳定同位素技术在果汁中的应用

分析测试学报 2008年第S1期27卷 221-223页

作者：钟石林中国计量科学研究院化学所北京100013

The principle and analysis standards of stable isotope ratio technique were reviewed in this *** application of isotope ratio mass spectrum in fruit juices authentication and origin traceability was introduced.

关键词： review application stable isotope ratio technique fruit juice