Biagio Fallico

Evaluation of antioxidant capacity of blood orange juices as influenced by constituents, concentration process and storage

Abstract Total Antioxidant Activities (TAA) of freshly squeezed and processed blood and blond orange juices were measured using the ABTS radical-cation method. Blood juices have TAA values higher than blond juices, and freshly-squeezed juices are higher than processed. Levels of ascorbic acid, hydroxycinnamic acid and anthocyanins were determined in order to calculate relative contributions to TAA by Trolox Equivalent Antioxidant Capacity (TEAC) of such constituents. Ascorbic acid was the main contributor (∼70%), followed by hydroxycinnamic acids and anthocyanins. Calculated TAA accounted for 91% (mean) of that measured, reaching a maximum of 98% (mean) for the ‘not-from-concentrate’ blood juices (NFC). Reconstituted (from concentrate) blood juices (RFC) had higher TAA than NFC, and the difference could be ascribed to the increased amount of carotenoid pigments in the serum of RFC juices, as a consequence of the thermal concentration process. Despite the degradation of anthocyanins during storage, TAA of NFC and RFC juices remained unchanged up to 60 days at 2°C, whereas it decreased when RFC juice was stored at 20°C, in accordance with the observed decrease of ascorbic acid.

Degradation of 5‐Hydroxymethylfurfural in Honey

5-Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid-catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food products. Usually its degradation reactions, being very slow, are neglected. This study reports the findings concerning the degradation kinetics of HMF, in honeys of different floral origin at a temperature between 25 and 50 degrees C. The results highlighted higher degradation rates (k(HMF) (degradation)) compared to the corresponding formation rates (k(HMF) (formation)) in chestnut and citrus samples. Similar k-values were found in multifloral honey. Moreover, the reaction of HMF degradation was characterized by lower activation energy (E(a)) values compared to E(a) formation values. The final concentration of HMF in honey, during storage at room temperature, should be ascribed to high sugar concentration. The fluctuation of HMF in honeys could depend on the equilibrium between the accumulation and the degradation processes. This can affect the validity of HMF as storage index in some honeys, above all during the analysis of those honeys whose legislation is too restrictive (citrus) or in chestnut honey analysis where it does not accumulate.

Influence of Ripeness and Drying Process on the Polyphenols and Tocopherols of Pistacia vera L.

This paper highlights, for the first time, the changes in the phenolics fraction (anthocyanins, flavonoids and stilbenes) and tocopherols of unpeeled Pistacia vera L. var. bianca with ripening, and the effect of the sun-drying process. The total polyphenol levels in pistachios, measured as mg of Gallic Acid Equivalent (GAE), were: 201 ± 10.1, 349 ± 18.3 and 184.7 ± 6.2 mg GAE/100 g DM in unripe, ripe and dried ripe samples, respectively. Most phenolics in ripe pistachios were found to be anthocyanins. They increased with ripening, while the sun drying process caused a susbtantial loss. Flavonoids found in all pistachio samples were daidzein, genistein, daidzin, quercetin, eriodictyol, luteolin, genistin and naringenin, which decreased both with ripening and drying. Before the drying process both unripe and ripe pistachios showed a higher content of trans-resveratrol than dried ripe samples. γ-Tocopherol was the major vitamin E isomer found in pistachios. The total content (of α- and γ-tocopherols) decreased, both during ripening and during the drying process. These results suggested that unpeeled pistachios can be considered an important source of phenolics, particularly of anthocyanins. Moreover, in order to preserve these healthy characteristics, new and more efficient drying processes should be adopted.

Survey of 1,2-Dicarbonyl Compounds in Commercial Honey of Different Floral Origin

In this study we conducted a survey of the concentrations of the major 1,2-dicarbonyl compounds in 40 commercial honey samples from 12 different floral origins. 3-Deoxyglucosone (3-DG), glyoxal (GO), and methylglyoxal (MGO) were measured, using their corresponding quinoxaline derivatives, by high-performance liquid chromatography (HPLC). The analytical performance of the HPLC method for the analysis of 1,2-dicarbonyl compounds was evaluated in terms of linearity, limits of detection (LODs), limits of quantification (LOQs), and precision. Linearity over 2 orders of magnitude, LODs (0.01-0.04 mg/kg), and LOQs (0.03-0.12 mg/kg) were calculated. Instrumental precision, as measured by the repeatability relative standard deviation% (RSDr%), was found to be between 0.22% and 0.55%. Furthermore, the concentrations of factors GO and MGO with respect to 3-DG were also calculated for rapid quantification in honey. In honey samples, the concentrations of 3-DG ranged from 75.9 to 808.6 mg/kg and were significantly higher (up to 100-fold) than those of 5-hydroxymethylfurfural (HMF). Values for GO and MGO were 0.1-10.9 and 0.2-2.9 mg/kg, respectively. The chemical characteristics that most influenced the levels of 1,2-dicarbonyl compounds in honey were found to be pH and total phenols. This was supported by multivariate analysis used to classify different honey types with respect to their chemical characteristics. In addition, both dicarbonyls and phenols are believed to contribute to the development of the final color of honey.

Bioactive compounds in blood oranges (Citrus sinensis (L.) Osbeck): Level and intake.

Both the composition and the intake of antioxidants (anthocyanins, ascorbic acid and hydroxycinnamic acids) were reported for all blood oranges including the single cultivars (Moro, Tarocco and Sanguinello) and industrially produced juices. The mean values of the studied bioactive compounds in the edible part oranges were: 9.6mg/100g of orange edible part for the anthocyanins; 8.1, 0.7, 1.3, 3.8, 2.5mg/100g for total hydroxycinnamic acids, caffeic, sinapic, ferulic and coumaric acids, respectively and 59.1mg/100g for ascorbic acid. The consumption of blood oranges contributes to a daily intake of: 9.4mg/d (up to 55mg/d) of anthocyanins and 58.5mg/d (up to 340mg/d) of vitamin C, respectively. Data suggest that the 50% of consumers, males and females, receive more than the 70% and 90% of EAR value of vitamin C, respectively. The 25% of males and the 40% of females has an intake higher than the EAR.

Kinetics of 3-deoxy-D-erythro-hexos-2-ulose in unifloral honeys.

In this study, for the first time, the amount of 3-deoxy-D-erythro-hexos-2-ulose (3-DG) in fresh citrus and chestnut honeys was determined. 3-DG was measured as the corresponding quinoxalines after derivatization with orthophenylenediamine using reverse-phase high-performance liquid chromatography (RP-HPLC). Notwithstanding the freshness of the samples, high levels of 3-DG were detected in both honeys. The comparison of 3-DG and 5-hydroxymethylfurfural (HMF) concentrations, which was also quantified by RP-HPLC, showed that citrus honeys had the lowest amount of 3-DG (107 mg/kg) and the highest of HMF (16.7 mg/kg), while chestnut honeys had the opposite (398 and 1.2 mg/kg, respectively). During thermal treatment, different 3-DG and HMF trends were highlighted between the citrus and chestnut honeys; at the end, 3-DG formation was more favored with respect to HMF formation. Moreover, in citrus honeys, a good correlation between 3-DG and HMF levels was observed, which was not found in chestnut honeys, suggesting a role of the high pH values of these honeys on the degradation routes. The kinetic analysis showed the highest k value for 3-DG and HMF formation in chestnut and citrus honeys, respectively. The lowest Ea values related to 3-DG formation and the highest to HMF formation, indicating that the key intermediate 3-DG is easily formed at low temperatures, whilst the formation of HMF requires higher temperatures. For this reason, 3-DG seems to be an aging index rather than a thermal index and its use, at least for honeys at high pH values, together with HMF, could improve their quality assessment.

Contribution of Blood Orange-Based Beverages to Bioactive Compounds Intake

The study aimed at screening the levels of ascorbic acid, hydroxycinnamic acids (HCAs) and total anthocyanins in commercial beverages containing blood orange juice (BOJ), estimating the contribution of these products to the intake of health-promoting compounds and at discussing the actual value of the products on a price/bioactive level basis. Results demonstrate that the reference to BOJ in many beverages is misleading, as inferred from the very low bioactive levels observed. These beverages, in label should refer as “water-based” instead of “fruit-based beverage.” Accordingly, the intake of bioactives from BOJ-based beverages, with the exception of ascorbic acid used in the most cases as preservative, is often very low. The intake of bioactive components from blood orange consumption is much higher compared to the consumption of BOJ-based beverages, hence the consumption of blood oranges and 100% BOJs should be preferred in order to guarantee the intake of a rich pool of bioactive compounds. Finally, the market value of BOJ-based beverages is not correlated with their real nutritional value: the relative unitary cost of the three classes of bioactive compounds considered increased in the order: fresh blood oranges < 100% BOJ < BOJ-based beverages. Hence, the consumption of fresh blood oranges represents the cheapest way to ensure the intake of health-promoting bioactive compounds such as anthocyanins and HCAs.

Application of prickly pear fruit extract to improve domestic shelf life, quality and microbial safety of sliced beef

The research aimed to expand the knowledge on the use of natural bioactive compounds for food preservation. First-crop fruit of prickly pear were subjected to water extraction and evaluated for total polyphenol content, antioxidant activity, in vitro antimicrobial performance against food spoilage and pathogenic bacteria, and betacyanin and betaxanthin content. The extract was then applied by dipping technique to packed sliced beef, to evaluate its effect on physical and chemical parameters, color and texture maintenance, as well as on microbial growth during shelf life at domestic storage conditions. The in vitro antimicrobial assay of prickly pear fruit extract evidenced a wide spectrum activity, since it inhibited the growth of all Gram positive and negative targeted strains. In vivo application of extract effectively reduced microbial growth during refrigerated storage; total mesophilic count was maintained below the limit established by Commission Regulation (EC) No 2073/2005 of 5 × 106 log CFU/g of beef up to 8 d, in comparison to control sample that reached the mentioned limit after 4 d. Moreover, extract addition preserved beef color and texture over the considered storage period, supporting the potential prospect to utilize the extract to improve overall quality and to prolong domestic shelf life of sliced beef.