1,720,978 research outputs found
Thermal inactivation of pectin methylesterase in pineapple juice
No full textThermal processing is usually used by the fruit juice industry for enzyme and microbial inactivation, thus limiting organoleptic changes that affect shelf life and quality of products. Mainly the inactivation of enzymes is necessary to avoid quality changes related to cloud loss, using mild temperature that allows minor alterations in product’s sensory as well as in nutritive traits. Pineapple juice, a product obtained by diluting the concentrate juice and pasteurizing afterword shipped to Europe, has a high residual pectin methylesterase (PME) activity. In this view, the present work provides a detailed kinetic study of the effect of pasteurization on inactivation of PME in pineapple juice. The fresh juice was treated with temperatures ranging from 70 to 95 °C, for various times, until the complete denaturation of PME occurred. Results of thermal stabilization treatments showed that enzyme inactivation behaviour follows a first-order kinetic process, in the studied temperature range. Moreover, the reaction rate constants for denaturation of PME were determined; in particular, activation energy (Ea), decimal reduction time (Dref), and z value (z), were 78.2 ± 4.5 kJ/mol, 16 s (at reference temperature of 106 °C) and 36 ± 3 °C, respectively. Based on the thermal resistance data here reported to inactivate PME, a treatment of 106 °C with a mean holding time of 1 min should be employed in order to preserve cloudiness of pasteurized pineapple juice
Characterization of polyphenolic compounds in cantaloupe melon by-products
No full textThe Muskmelon (Cucumis melo L.), which includes several crops of great economic importance worldwide, belongs to the Cucurbitaceae family, and it is well recognized for culinary and medicinal purposes. The high fruit consumption produces a large quantity of waste materials, such as peels and seeds that are still rich in molecules like polyphenols, carotenoids, and other biologically active components that possess a positive influence on human health and wellness. A sustainable development in agro-food and agro-industry sectors could come through the reutilization and valorization of these wastes, which in turn, could result in reducing their environmental impact. The current study provides a biochemical characterization of cantaloupe by-products, peels and seeds, through evaluating total polyphenols, ortho-diphenols, flavonoids, and tannins content. Furthermore, the antioxidant activity was assessed in order to understand potential benefits as natural antioxidants. Overall, the peel extract revealed the highest radical's scavenging and reducing activities, moreover, it showed higher polyphenolic content than seed extract as revealed by both cromatographic and spectrophotometric analyses. The results of the present study indicate that the melon residues are a good source of natural phytochemicals useful for many purposes, such as ingredients for nutraceutic, cosmetic, or pharmaceutical industries, development of functional ingredients and new foods, and production of fertilizers and animal feed
The effect of processing methods on phytochemical composition in bergamot juice
No full textExperimental and epidemiological studies show a positive relation between consumption of citrus juices and reduction of risk for some chronic disorders, such as diabetes and cardiovascular diseases. In particular, the bergamot juice is characterized by noticeable amounts of phytochemicals such as flavanone glycosides, limonoids, and quaternary ammonium compounds, all health-beneficial biomolecules. In vitro and in vivo studies have shown anti-inflammatory, cholesterol-lowering, and anti-diabetic activities attributed to these compounds depending on their chemical structure. However, nutritional content of bergamot juice may vary as consequence of different processing techniques, thus needing to address this claim. For this reason, the objective of this research was to evaluate the effects of different processing systems on the proximate constituents, the composition, and the antioxidant activity of the correspondent juices. Overall, the results indicate that the process employed may influence the chemical composition and the functional properties of the ended juice. Screw press method produced a juice with greater content of flavanone glycosides (ranged from 37 to 402 mg/L) and limonoid aglycones (ranged from 65 to 67 mg/L) than the other processes (p < 0.001). However, the process used for extraction of bergamot juice did not affect significantly the N,N-dimethyl-L-proline content (p < 0.5). Moreover, the screw press juice showed the highest antioxidant activity with EC50 value of 9.35 μg/mL, thus suggesting that this method maintains for health the nutritional quality of a fresh-pressed juice
Characterization of essential oil recovered from fennel horticultural wastes
No full textFennel crop has been traditionally used as spice in cooking and fragrances, and in folk medicine for its spectrum of useful properties. Mediterranean is the elective natural cultivation area for this plant with Italy being a leader producer. A limit of this production is due to the high amount of wastes derived still rich of phytochemicals, which are usually underused. Hence, the extraction and characterization of essential oil from residues of fennel horticultural market was investigated to understand the potential profit of their recycling. Forty-eight compounds resulted for fennel oil waste, analysed by GC-FID-MS, with the most abundant among components was anethole. Other constituents contributing to fennel flavour were the monoterpenes limonene and nerol. The exploitation of this oil as a good source of bioactive compounds was assessed by means of its antioxidant power measured with DPPH test
Elemental content and nutritional study of blood orange juice
No full textBackground: The elemental content of Sicilian red orange juices and the bioaccessibility of many elements of particular nutritional interest was evaluated. Results: The elemental content of fresh juices from Sicilian blood oranges was analysed by ICP-OES, GF AAS, HG-AAS and CV AAS. Among the macroelements (Na, Ca, K, Mg and P), potassium occurred in the greatest amount, with 3.64% of the requested RDA for 100 mL of juice daily intake. Thevalues of RDA 100 mL-1 of juice for Mg, P, Ca and Na resulted1.61%, 1.26%, 0.59% and 0.09% respectively. For the traceelementsCr, Cu andSe, theRDA 100 mL-1 of juice were 9.20%, 7.14% and1.82%, respectively. In vitro tests simulating the digestive process showed high bioaccessibility only for boron and manganese while that of copper, zinc and iron were consistently lower. CONCLUSIONS:Sicili an blood orange juices gave different results from non-pigmented orange juices interms of a higher content of copper, boron and lower content of chromium and manganese. However, among the nutritionally important elements, only manganese showed high bioaccessibility. The low bioaccessibility found for iron, zinc and copper is likely due to the presence in the orange juice of ligands such as polyphenols and organic acids. © 2009 Society of Chemical Industry
Experimental design to extract natural compounds from Calendula flowers
No full textThe genus Calendula grows along the coasts of the Mediterranean Sea, including Calendula officinalis (Linn.), Calendula arvensis (Linn.), and Calendula maritima (Guss). Among these species, only the first one is studied in detail for bioactive molecules, pharmacological properties, and it is therefore considered for commercial product as medicines and cosmetics
Effect of Olive Mill Wastewater Spreading on Soil Properties
No full textThe effect of untreated olive mill wastewater (OMW) spreading on chemical and biological soil properties of two different fields located in Campania (Italy) was investigated. Fields were irrigated since 2003 with quantities of about 30 m3 ha−1 year−1, a volume lower than the maximum limit of 80 m3 ha−1 year−1 established by Italian law. Results showed that the addition of OMW, even if repeated for many years, had little impact on pH, electrical conductivity, organic matter, concentrations of main cations and polyphenolic content of both soil plots; moreover, microbial respiration was low during the winter time, but an increase was evident in the second sampling carried out in warm season. This study suggests that OMW, without pre-treatments, can be annually used for crops and tree irrigation. As a consequence, OMW should be a readily and inexpensive source of nutrients that could replace chemical fertilizers which are extensively employed in agricultural practices of Mediterranean countries
Rapid evaluation of ergosterol to detect yeast contamination in fruit juices
Full text linkFoods and beverages are nutrient-rich systems prone to a rapid development of microorganisms that hamper their long-period storage. Particularly, yeasts are strong fermenters of fresh and processed fruits and vegetables; hence, they are often accountable for their spoilage and production of off-flavor. This work provides a quick and easy tool to recognize and count the spoilage of juices with ergosterol as distinctive biomarker of molds and yeasts. Melon juice was reconstituted at natural physical–chemical parameters according to legislation, and Saccharomyces cerevisiae was selected as yeast to contaminate the juice. Chemical and enzyme tests were performed on the fresh juice to ensure its authentic properties. Ergosterol was then evaluated using a spectrophotometric method that was proven against the official plate count test. The study showed linear and consistent results and, therefore, the ergosterol molecule may be indicated for testing molds and yeasts in contaminated beverages, replacing the common and time-consuming analysis
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