Development of an orange juice in-house reference material and its application to guarantee the quality of vitamin C determination in fruits, juices and fruit pulps

Development of an Ephedrine In-House Matrix Reference Material and Its Application to Doping Analysis

Biomatrix-based reference materials (RMs) improve the quality of laboratory test results by better representing actual samples. However, a matrix RM of ephedrine (EP) for threshold substances that require accurate analysis results has not yet been developed. Therefore, this study aimed to develop an in-house matrix RM for EP and subsequently apply it to analytical procedures. During the development of the in-house matrix EP RM, the system underwent homogeneity and stability studies. Additionally, it was subjected to interlaboratory comparison study in 11 laboratories, including 10 World Anti-Doping Agency (WADA)-accredited laboratories and our laboratory. Stability testing revealed no significant changes in the RM characteristics. For homogeneity, 10 random batches out of 200 were analyzed to confirm the uniformity within and between bottles. These results, combined with data from 11 laboratories, ensured retroactive validation. The traceability value of the in-house matrix EP RM was assigned as 9.83 ± 0.57 μg/mL (k = 2) by interlaboratory comparison studies and traceable uncertain evaluation. The feasibility of this method as a single calibration standard was confirmed in two laboratories. This substance is reliable and consistent for quality control during EP quantification, ensuring accurate and trustworthy outcomes. Consequently, this study establishes a framework and guidelines for producing in-house matrix RMs and serves as a reference for generating similar matrix RMs in other contexts.

A New Ultra-Performance Liquid Chromatographic Method for the Quantification of Vitamin C in Fresh and Dried Goji Berries (Lycium barbarum L.) Cultivated in Turkey

BACKGROUND

The potential background of the study is related to comprehensive detection of the content of vitamin C with an actual chromatographic method.

OBJECTIVE

Vitamin C is of vital importance in terms of human life and health due to its polyfunctional activity such as antioxidant activity and antiviral effect with other biological functions. In this regard, it may be necessary to update analytical methods or develop up-to-date analytical methods to accurately estimate the amount of vitamin C in natural samples. In this study, a new ultra-performance liquid chromatography with photodiode array detection (UPLC-PDA) method has been developed for the determination of vitamin C content in fresh and dried goji berries (Lycium barbarum L.), which are cultivated in Turkey.

METHOD

The chromatographic elution of vitamin C in natural fruit samples was achieved on an ACQUITY UPLC BEH C18 (1.7 µm, 2.1 mm × 100 mm) column using methanol and 0.1 M H3PO4 pH 2.15 (20:80, v/v), which are mobile phase. UPLC determination was done at the 242.8 nm. Flow rate was 0.20 mL/min at a column temperature of 30°C. Linearity range of the calibration graph was found to be at 5-30 µg/mL. The validity of the newly developed UPLC method was tested by analyzing individual test samples and added samples.

RESULTS

Applicability of the validated UPLC method was verified by the quantitative analysis of vitamin C content in both fresh and dried goji berries.

CONCLUSIONS

We believe that the newly developed and validated UPLC method would be a useful and promising approach for simple quantitative analysis of goji berry samples for vitamin C.

HIGHLIGHTS

In previous studies, no UPLC-PDA method was reported for the analysis of vitamin C in goji berries. The method provided a good repeatability for the analysis of real samples.

Analysis of the Phytochemical Composition of Pomegranate Fruit Juices, Peels and Kernels: A Comparative Study on Four Cultivars Grown in Southern Italy

The increasing popularity of pomegranate (Punica granatum L.), driven by the awareness of its nutraceutical properties and excellent environmental adaptability, is promoting a global expansion of its production area. This investigation reports the variability in the weight, moisture, pH, total soluble solids, carbohydrates, organic acids, phenolic compounds, fatty acids, antioxidant activities, and element composition of different fruit parts (juices, peels, and kernels) from four (Ako, Emek, Kamel, and Wonderful One) of the most widely cultivated Israeli pomegranate varieties in Salento (South Italy). To the best of our knowledge, this is the first systematic characterization of different fruit parts from pomegranate cultivars grown simultaneously in the same orchard and subjected to identical agronomic and environmental conditions. Significant genotype-dependent variability was observed for many of the investigated parameters, though without any correlation among fruit parts. The levels of phenols, flavonoids, anthocyanins, and ascorbic and dehydroascorbic acids of all samples were higher than the literature-reported data, as was the antioxidant activity. This is likely due to positive interactions among genotypes, the environment, and good agricultural practices. This study also confirms that pomegranate kernels and peels are, respectively, rich sources of punicic acid and phenols together, with several other bioactive molecules. However, the variability in their levels emphasizes the need for further research to better exploit their agro-industrial potential and thereby increase juice-production chain sustainability. This study will help to assist breeders and growers to respond to consumer and industrial preferences and encourage the development of biorefinery strategies for the utilization of pomegranate by-products as nutraceuticals or value-added ingredients for custom-tailored supplemented foods.

Effect of Adding Resistant Maltodextrin to Pasteurized Orange Juice on Bioactive Compounds and Their Bioaccessibility

Resistant maltodextrin (RMD) is a water-soluble and fermentable functional fiber. RMD is a satiating prebiotic, reducer of glucose and triglycerides in the blood, and promoter of good gut health, and its addition to food is increasingly frequent. Therefore, it is necessary to study its potential effects on intrinsic bioactive compounds of food and their bioaccessibility. The aim of this study was to evaluate the effect of adding RMD on the bioactive compounds of pasteurized orange juice with and without pulp, and the bioaccessibility of such compounds. RMD was added at different concentrations: 0 (control sample), 2.5%, 5%, and 7.5%. Ascorbic acid (AA) and vitamin C were analyzed using HPLC, whereas total phenols, total carotenoids (TC), and antioxidant capacity were measured using spectrophotometry. After that, sample in vitro digestibility was assessed using the standardized static in vitro digestion method. The control orange juice with pulp presented significantly higher values of bioactive compounds and antioxidant capacity than the control orange juice without pulp (p < 0.05). RMD addition before the juice pasteurization process significantly protected all bioactive compounds, namely total phenols, TC, AA, and vitamin C, as well as the antioxidant capacity (AC) (p < 0.05). Moreover, this bioactive compound protective effect was higher when higher RMD concentrations were added. However, RMD addition improved phenols and vitamin C bioaccessibility but decreased TC and AA bioaccessibility. Therefore, the AC value of samples after gastrointestinal digestion was slightly decreased by RMD addition. Moreover, orange pulp presence decreased total phenols and TC bioaccessibility but increased AA and vitamin C bioaccessibility.

Microwave-assisted Synthesis of N,S-co-carbon Dots as Switch-on Fluorescent Sensor for Rapid and Sensitive Detection of Ascorbic Acid in Processed Fruit Juice

To achieve a rapid, sensitive, and economical method for the detection of ascorbic acid (AA) in the presence of Fe³⁺, a nitrogen and sulfur co-doped carbon dots (N,S-co-CDs) based fluorescence sensing system was developed. In this work, N,S-co-CDs were successfully synthesized via a one-step microwave-assisted method within 2.5 min using ammonium citrate and L-cysteine as precursors. The fluorescence of N,S-co-CDs was quenched (off ) by Fe³⁺ through a static-quenching mechanism. Subsequently, the fluorescence was recovered (on) after introducing AA into the quenched system, which was attributed to the reduction effect of AA for Fe³⁺. Therefore, a switch-on sensor (N,S-co-CDs/Fe³⁺ system) was developed for AA detection. Under optimal conditions, the limit of detection (LOD) of 2.31 μmol/L for AA was obtained over a linear range from 0 to 150 μmol/L. Furthermore, the proposed sensing method was successfully applied to detect AA in processed fruit juice with satisfactory results. The most important is that the sensor derived from a microwave-assisted method has simple and eco-friendly synthesis processes, is rapid, and has high detection efficiency. Therefore, such a switch-on sensor may be a promising candidate sensor for AA detection in processed fruit samples.

Nitrogen nutrition is a key modulator of the sugar and organic acid content in citrus fruit

'Huangguogan' (Citrus reticulata × C. sinensis) is a new cultivar of mandarin citrus in China, and the research on fertilization of 'Huangguogan' is very limited. In this study, the effect of N fertilization on 'Huangguogan' fruit quality was determined at ripening. Sugars (sucrose, fructose, and glucose), organic acids (pyruvic, oxalic, citric acid, etc.), and vitamin components were measured at six stages of fruit development, and eight enzymes related to the glycolytic and Krebs cycle were assessed. The 1.81 kg N y-1 treatment group showed the highest total soluble solids concentration and total soluble solids/titratable acidity ratio but the lowest titratable acidity (acid content) at ripening, while the N1 treatment (0 kg N y-1) showed the opposite trend. Sucrose and citric acid accumulated to the largest extent during fruit development. Sucrose and ascorbic acid content increased (8.46 to 50.97 mg g-1 and 8.16 to 27.39 mg g-1, respectively), while citric acid content decreased (90.81 to 0.02 mg g-1). Aconitase was the key enzyme responsible for the observed changes in citric acid. The N concentrations in ripening fruit ranged from 2.25% to 4.15%. Curve estimation and principal component analysis revealed that fruit N was positively correlated with the sugars and vitamin components and negatively correlated with the organic acids. The accumulation of these metabolites seemed closely related to the dynamic changes in fruit N concentration at the five N levels tested. In conclusion, we suggest that the 1.81 kg N y-1 treatment represents the most suitable N fertilizer treatment for 'Huangguogan' citrus fruit.

Bio-mediated synthesis of 5-FU based nanoparticles employing orange fruit juice: a novel drug delivery system to treat skin fibrosarcoma in model animals

Nano-sized drug delivery systems (NDDS) have been widely exploited to achieve targeted delivery of pharmaco-materials. Traditional pharmaceutical approaches, implied in the synthesis of nano-formulations, are obscure owing to the incompatible physico-chemical properties of the core drug as well as some other factors crucial in development of NDDS. Infact, most of the existing methods used in development of NDDS rely on usage of additives or excipients, a special class of chemicals. Barring few exceptions, the usage of synthetic excipients ought to be curtailed because of several associated undesirable features. Such issues necessitate strategies that lead to development of the synthetic excipient free drug delivery system. Plant based extracts have great potential to induce synthesis of nano-sized particles. Considering this fact, here we propose a prototype employing orange fruit juice (OJ) to facilitate bio-mediated synthesis of nano-sized supra-molecular assemblies of 5-fluorouracil (5-FU), a potent anticancer drug. The as-synthesized 5-FU Nanoparticles (NPs) retained the anti-neoplastic efficacy of the parent compound and induced apoptosis in cancer cells. The novel 5-FU NPs formulation demonstrated enhanced efficacy against DMBA induced experimental fibrosarcoma in the mouse model when compared to the micro-sized crystals of parent 5-FU drug.

Polymeric template assisted synthesis of monodisperse-porous manganese oxide microspheres: a new nanozyme with oxidase-like activity allowing biomolecule determination via bimodal sensing

New template assisted synthesis of monodisperse-porous MnO₂ microspheres and their usage as a nanozyme in the first bimodal sensing of ascorbic acid.

Effect of enzymatic treatment on the rheological behavior and vitamin C content of Spondias tuberosa (umbu) pulp

Umbu is a native fruit of the semi-arid Northeastern region of Brazil, which presents an exotic and differentiated flavor. Containing vitamin C and presenting a high potential of consumption, no appropriated technology has been developed to process this fruit and expand its commercialization to other markets. The enzymatic treatment of fruit pulps leads to viscosity reduction, which makes possible an efficient processing for obtaining high quality umbu juices. In order to contribute to the valorization of this underexploited culture, two commercial pectinolytic enzymes, Pectinex Ultra SP-L^® and Rapidase TF^®, were used to promote viscosity reduction of umbu pulp. The effect of reaction temperature (35, 45 and 55 °C) and enzyme concentration (100, 200 and 300 ppm) on the rheological properties of the fruit pulp was evaluated. In relation to the viscosity of the original pulp (84.8 mPa s at 100 s^-1 shear rate), a significant, four times lower, viscosity reduction of 18.9 mPa s was observed. Under optimum process condition (35 °C and Rapidase at 100 ppm concentration), the lowest viscosity was achieved after 40 min of reaction. Under these reaction conditions, no significant change was found in the vitamin C content, indicating the preservation of functional and nutritional properties of umbu pulp.

Effect of di-n-butyl phthalate (DBP) on the fruit quality of cucumber and the health risk

Di-n-butyl phthalate (DBP) widely used as plastic films' plasticizer, can cause agricultural pollution which is of increasing concern because of the food safety issues. Cucumber ( Cucumis sativus Linn.), commonly cultured in greenhouse, was exposed to DBP stress to gain more information about the ecological risk of DBP in this study. Changes of DBP residues and fruit quality of cucumber at different DBP concentrations (0, 5, 10, 20, 40 mg/kg of dry soil) were investigated in pot experiments using an agricultural soil under greenhouse condition, respectively. DBP residue in cucumber fruits ranged from 0.5326 to 1.8938 mg/kg, and the quality of cucumber fruits (organic acids, vitamin C, soluble protein, and soluble sugar) were influenced by DBP stress. Moreover, the health risk assessment was evaluated by estimate daily intakes (EDI) and the target hazard quotient (THQ) was analyzed. Under 40 mg/kg DBP condition, the highest value of EDI was 2.49 μg/kg bw/day and the THQ ranged from 0.000700 to 0.0249. Although the risk of DBP in cucumber fruits was lower than the threshold limit value of risk, the potential health risk was not a negligible issue.

Methyl-inositol, γ-aminobutyric acid and other health benefit compounds in the aril of litchi

The available components in the flesh of litchi seem insufficient to interpret its wide and significant physiological effects. Some unusual compounds, including myo-inositol, inositol methyl derivatives and γ-aminobutyric acid (GABA) were identified as main constituents in the flesh of litchi. Their concentrations varied among cultivars but remain relatively constant during development. Litchi flesh was shown to contain moderate myo-inositol (0.28-0.78 mg g(-1) FW), ascorbic acid (0.08-0.39 mg g(-1) FW) and phenolics (0.47-1.60 mg g(-1) FW), but abundant l-quebrachitol (1.6-6.4 mg g(-1) FW) and GABA (1.7-3.5 mg g(-1) FW). The concentration of GABA in the flesh of litchi was about 100 times higher than in other fruits. And l-quebrachitol is not a common component in fruits. The biological and physiological activities of inositols, inositol derivatives and GABA have been extensively documented. These compounds are probably important compositional characteristic contributing to the widely shown health benefits of litchi.

Stabilization of Natural Antioxidants by Silk Biomaterials

The stabilities of three natural antioxidants, vitamin C (VC), (-)-epigallocatechin gallate (EGCG), and curcumin, in silk films were examined and mechanisms of stabilization were elucidated. The antioxidants were physically incorporated into three types of silk films: as-cast, dried from hydrogels, and methanol-treated. Films were stored at 4, 37, and 45 °C for 30 days in phosphate-buffered saline, pH 7.4, along with controls consisting of free antioxidants. Incorporation of antioxidants did not significantly change film morphology or secondary structure. When stored at 4 °C, all samples showed similar antioxidant activities (percent scavenging) at different time points, determined by the colorimetric 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. At higher temperatures, VC in the as-cast film, EGCG in the as-cast and dried hydrogel films, and curcumin in the methanol-treated films retained more than 50% scavenging activity after 14 days of storage, significantly higher than the other samples. Interaction between antioxidants and silk, as well as degradation of the antioxidants, was investigated by fast-performance liquid chromatography (FPLC) and high-pressure liquid chromatography (HPLC), with an aim of understanding the mechanisms of silk-based stabilization. Binding of antioxidant molecules to hydrophobic or to hydrophilic/hydrophilic boundary regions of silk, depending on the chemical properties of the antioxidant, may account for the observed stabilization effects. The data can help guide further engineering of antioxidant-functionalized silk biomaterials.

Comparative Evaluation of Physicochemical Properties of Pine Needle Powders Prepared by Different Drying Methods

Systematic study of how different drying methods, namely hot-air drying, vacuum-drying, and freeze-drying, affect color, browning index, degree of rehydration, water solubility, and vitamin C content is critical for utilizing pine needle powders (PNP) as a novel ingredient in functional foods. Samples prepared by vacuum-drying showed a significantly higher L*-value, whereas higher a*- and b*-values were detected in the hot-air dried samples (P<0.05). The browning index was significantly higher in samples prepared by vacuum-drying compared to samples prepared by freeze-drying (P<0.05). Freeze-dried PNP exhibited a significantly higher degree of rehydration than hot-air dried samples (P<0.05). Water solubilities of freeze-dried and hot-air dried samples were significantly higher than that of vacuum-dried sample (P<0.05). Vitamin C was less destroyed during freeze-drying compared to hot-air or vacuum-drying (P<0.05). Freeze-dried samples displayed a clear porous structure and appeared to have a bigger space, whereas hot-air dried samples showed lower porosity than vacuum and freeze-dried samples.

Effect of UV-C radiation on bioactive compounds of pineapple (Ananas comosus L. Merr.) by-products

BACKGROUND

The industrial processing of pineapple generates a high quantity of by-products. To reduce the environmental impact of these by-products and the inherent cost of their treatment, it is important to characterise and valorise these products, converting them into high added value products. Ultra-violet radiation is one of the main sustainable sanitation techniques for fruits. Since this radiation can induce plant stress which can promote the biosynthesis of bioactive compounds, it is important to evaluate its effect in fruits.

RESULTS

The amounts of vitamins (C and E) and carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, neoxanthin, violaxanthin and zeaxanthin) in pineapple by-products (core and rind) were analysed before and after treatment with UV radiation. All treated and untreated pineapple by-products contained β-carotene as the main carotenoid (rind, 2537-3225 µg; and core, 960-994 µg 100 g(-1) DW). Pineapple rind also contained lutein (288-297 µg 100 g(-1) DW) and α-carotene (89-126 µg 100 g(-1) DW).

CONCLUSION

The results provide evidence of the potential of pineapple by-products as a source of bioactive compounds with antioxidant activity, which can be used by pharmaceutical, cosmetics and food industries. In addition, UV-C was shown to be a treatment that can add nutritional value to pineapple by-products.

Determination of vitamin C in foods: current state of method validation

Vitamin C is one of the most important vitamins, so reliable information about its content in foodstuffs is a concern to both consumers and quality control agencies. However, the heterogeneity of food matrixes and the potential degradation of this vitamin during its analysis create enormous challenges. This review addresses the development and validation of high-performance liquid chromatography methods for vitamin C analysis in food commodities, during the period 2000-2014. The main characteristics of vitamin C are mentioned, along with the strategies adopted by most authors during sample preparation (freezing and acidification) to avoid vitamin oxidation. After that, the advantages and handicaps of different analytical methods are discussed. Finally, the main aspects concerning method validation for vitamin C analysis are critically discussed. Parameters such as selectivity, linearity, limit of quantification, and accuracy were studied by most authors. Recovery experiments during accuracy evaluation were in general satisfactory, with usual values between 81 and 109%. However, few methods considered vitamin C stability during the analytical process, and the study of the precision was not always clear or complete. Potential future improvements regarding proper method validation are indicated to conclude this review.

Nutritional and phytochemical composition of Annona cherimola Mill. fruits and by-products: Potential health benefits

Annona cherimola Mill., commonly known as cherimoya, is a tropical fruit well known due to its tasty flavour. In the present study the antioxidant activity of pulp, peel and seeds of four cultivars from A. cherimola Mill. from Madeira Island (Madeira, Funchal, Perry Vidal and Mateus II) was analysed. Moreover, nutritional composition (proximates and vitamins) and bioactive compounds content were determined. The peel of Madeira cultivar showed the highest antioxidant capacity, with an EC50 of 0.97mg/mL, and total flavonoids (44.7 epicatechin equivalents/100g). The most abundant carotenoid was lutein, with values ranging from 129 to 232μg/100g. The highest l-ascorbic acid content (4.41mg/100g) was found in the peel of Perry Vidal cultivar. These results highlight A. cherimola Mill. antioxidant properties, especially in its by-products and encourage their application in cosmetic, pharmaceutical and food processing industries, as added value natural extracts.