Production and characterization of glicosidases from Aspergillus terreus using "pastazzo" as inductor .

Increase of trans-resveratrol in typical Sicilian wine using β-Glucosidase from various sources

β-Glucosidase (EC 3.2.1.21) (β-G) from different sources were tested to increase the trans-resveratrol in some Sicilian wines by hydrolysing resveratrol glucoside. β-G from Aspergillus niger mould was tested as a crude and purified enzyme, and compared with the same enzyme from Saccharomyces cerevisiae yeast. Specific purification served to eliminate collateral enzyme activities so that β-G could be used simply and economically. Aspergillus niger β-G produced trans-resveratrol increases of up to 75%, with no change in physico-chemical properties and bouquet, and an increase in health and nutritional properties. S. cerevisiae β-G raised free-terpenol levels, but impaired wine colour due to a…

PARTIAL SEQUENCING OF THE BETA-GLUCOSIDASE-ENCODING GENE FROM YEAST STRAINS ISOLATED FROM MUSTS AND WINES

The aim of the present work was the identification of the gene encoding for β-glucosidase and its partial sequencing in the strainsPichia anomala AL112,Hanseniaspora uvarum Y8 andSaccharomyces cerevisiae AL41. To this aim degenerated primers, designed on the basis of aminoacid similarities of four known yeast β-glucosidases, have been used in PCR amplifications. An expected fragment of about 200 bp was amplified from all the DNAs, cloned and sequenced. Sequence homology demonstrated for the first time the presence of a β-glucosidase encoding gene inHanseniaspora uvarum andSaccharomyces cerevisiae.

Recovery of anthocyanins from eggplant peel

Abstract Tartaric and malic acid solutions were tested to extract anthocyanins from eggplant peel by a discontinuous process to obtain a natural red colorant. Extraction optimization was carried out, using different solvents, acid concentration, temperature, time of extraction and solvent-to-solid ratio as independent variables. Tartaric acid was more efficient than malic acid in both extraction yield and rate. Comparative tests were carried out using acidified ethanol as solvent. Delphinidin-3-rutinoside was extracted and identified as the major anthocyanin in eggplant peel. Concentration of different extracts from eggplant peel was carried out using EXA-31, a methacrylic food grade resin,…

Toward shrimp consumption without chemicals: Combined effects of freezing and modified atmosphere packaging (MAP) on some quality characteristics of Giant Red Shrimp (Aristaeomorpha foliacea) during storage.

The combined effects of freezing and modified atmosphere packaging (MAP) (100% N2 and 50% N2 + 50% CO2) on some quality characteristics of Giant Red Shrimp (GRS) (Aristaeomorpha foliacea) was studied during 12-month storage. In particular, the quality characteristics determined proximal and gas compositions, melanosis scores, pH, total volatile basic-nitrogen (TVB-N), thiobarbituric acid (TBA) as well as free amino acid (FAA). In addition, the emergent data were compared to those subject to vacuum packaging as well as conventional preservative method of sulphite treatment (SUL). Most determined qualities exhibited quantitative differences with storage. By comparisons, while pH and TVB-N sta…

Preliminary characterization of wild lactic acid bacteria and their abilities to produce flavour compounds in ripened model cheese system.

Aims:  The aim of this work was to preliminary characterize wild lactic acid bacteria (LAB), previously isolated during artisanal Pecorino Siciliano (PS) cheese-making for technological and flavour formation abilities in a model cheese system. Methods and Results:  Twelve LAB were studied for the ability to grow at 10 and 45°C, to coagulate and acidify both reconstituted skim milk and ewe's milk. Moreover, the capacity of the strains to generate aroma compounds was evaluated in a model cheese system at 30- and 60-day ripening. Flavour compounds were screened by sensory analysis and throughout gas chromatography (GC)–mass spectrometry (MS). Most of the strains were able to grow both at 10 an…

Study and characterization of polyphenol oxidase from eggplant (Solanum melongena L.)

ABSTRACT: In this study the catecholase and cresolase activities of eggplant polyphenol oxidase (PPO) were investigated. Enzyme activity was determined by measuring the increase in absorbance using catechol as substrate and 3-methyl-2- benzothiazolinone hydrazone (MBTH) as coupled reagent. The effects of substrate specificity, heat inactivation, temperature, pH, and inhibitors were investigated to understand the enzymatic alteration of ready-to-eat preparations. Browning of vegetables was determined through a colorimeter. Decrease of lightness (L*) and increase of color difference values (ΔE*) were correlated with tissue browning. Antibrowning agents were tested on PPO under the same condit…

New application of agro-industrial waste to prevent melanosis of Mediterranean pink shrimp

Effects of thermal treatments on pectinesterase activity determined in blood oranges juices

Abstract The citrus processing industry aims to maintain turbidity and attractive colour of the juice obtained from Sicilian blood oranges. Nevertheless, the presence of pectinesterase (PE, E.C. 3.1.1.11) causes the loss of these peculiar characteristics, due to precipitation of colloids and very fine pieces of pulp in suspension, with negative effects on colour and clarification of the juices. This study compares total PE activity of Sicilian blood oranges ( Sanguinello , Moro , Tarocco ) with the blonde cultivar Navel , checking enzyme stability with various pasteurisation times and temperatures conditions. Decimal reduction time and temperature ( D and z ) as well as the kinetic constant…

Water as a Solvent of Election for Obtaining Oleuropein-Rich Extracts from Olive (Olea europaea) Leaves

Leaves from Olea europaea represent one of the main by-products of the olive oil industry, containing a plethora of bioactive compounds with several promising activities for human health. An organic solvent-free extraction method was developed for the recovery of olive leaf phenols, which obtained an extract containing oleuropein in high amounts. A comparison of various extraction media is reported, together with the total phenolic content, DPPH (2,2-Diphenyl-1-picrylhydrazyl) content, ORAC (oxygen radical absorbance capacity), and polyphenol oxidase activity of the corresponding extracts. The polyphenol profiles and content of the most representative extracts have also been studied. Extrac…

The effect of different technologies in Pomegranate jam preparation on the phenolic compounds, vitamin C and antioxidant activity

The effect of different gelling agents and processing for jam production from pomegranate juice was evaluated. In the last years, different gelling agents were tested for improving jam quality in terms of color and bioactive compounds. The unsonicated and sonicated pomegranate juices were processed for jam production by micro waves, under vacuum and cryoconcentration concentration methods using low and high methoxy pectins, and carob seed flour as gelling agents. The polyphenols content of sonicated jam was significantly lower than unsonicated samples and cryoconcentrated jams showed the significantly highest value among other methods. The results showed the highest anthocyanin content in t…

DEGRADATIVE ENZYMATIC ACTIVITIES IN FRESH-CUT BLOOD ORANGE SLICES DURING CHILLED STORED

Summary Blood-orange fruits are suitable to fresh-cut fruit production because of their chemical compositions. Nevertheless, the main limitation of using freshly cut oranges is their susceptibility to juiciness loss and ascorbic acid degradation because of enzymatic alterations. The aim of this work is: to identify some of the enzymes causing the qualitative decay in blood-orange slices during 15 days of chilled storage (at 4 ± 0.5 °C and 85% RH); to investigate the susceptibility to the previous alterations of five blood-orange clones (Moro nucellare, Sanguinello nucellare, Tarocco arcimusa, Tarocco gallo and Tarocco meli) to select the most suitable one for fresh-cut production. The enzym…

Myrosinase activity and quality parameters on fresh-cut Chinese cabbage stored at two different temperatures

Effect of freezing/thawing process in different sizes of blue fish in the Mediterranean through lysosomal enzymatic tests

The assessment of freshness of different sizes of blue fish (Engraulis encrasicolus 12 cm, Sardina pilchardus 15 cm, Trachurus trachurus 40 cm, Scomber japonicus colias 60 cm) was carried out using non-conventional enzymatic methods. The activities of the three lysosomal enzymes (α-glucosidase (AG), β-galactosidase (B-GAL) and β-N-acetylglucosamidase (B-NA)) in extracts of blue fish muscle were measured over a period of 21 days of storage. A significant increase (p < 0.05) of AG activity was observed in all species, with a large increase seen after only one day of storage. B-NA activity increased slightly in sardines, horse mackerels and chub mackerel during frozen/thawed storage. Finally, …

Effect of Drying Condition on the Quality of Dry Late Peaches of Leonforte

The Late Peach of Leonforte [Prunus persica (L.) Batsch] grown in Southern Italy matures in September and October and as late as November. Fruits are wrapped in paper bags to protect them from parasites and are harvested only when fully ripe. Protected inside the bags, they ripen late and take on a bright yellow colour with red streaks. Highly aromatic, the peach has yellow, firm flesh that is high in soluble solids and has a distinctive, slightly caramelized flavour. The aim of this work was to deter¬mine the best method of drying peach as a means of conserving the fruit after harvest due to its very limited shelf-life. Drying processes were carried out in a pilot plant utilising differen…

Natural Indigo from Isatis tinctoria L. for the Reassessment of Sicilian Crops - A Minireview

POLYPHENOL OXIDASE ACTIVITY FROM THREE SICILIAN ARTICHOKE (CYNARA CARDUNCULUS L. VAR. SCOLYMUS L. (FIORI)) CULTIVARS: STUDIES AND TECHNOLOGICAL APPLICATION ON MINIMALLY PROCESSED PRODUCTION.

Several papers helped with the development of more methods to control browning, or study thermal polyphenol oxidase (PPO) inactivation, but did not provide any solutions to technological process problems and food process improvement. Artichokes [ Cynara cardunculus L. var. scolymus L. (Fiori)] are susceptible to browning; this alteration could affect and reduce the suitability for its use, fresh or processed. Within this study, the catecholase and cresolase activities of PPO from three different Sicilian artichokes cultivar were characterized with regard to substrate specificity and enzyme kinetics, optimum pH and temperature, temperature and pH stability, and inhibitor test; all of the res…

Tecnologie alimentari: problemi svolti di operazioni unitarie

Le Operazioni Unitarie (OU) costituiscono gli elementi base del flow-sheet di un processo produttivo. Le OU fondamentali comuni a più processi si basano sugli stessi principi, relativi a fenomeni chimico-fisici e biologici, e quindi su tecnologie simili, anche se naturalmente le apparecchiature, i materiali di costruzione e le condizioni operative devono essere adattate. Questa scomposizione logica, permette di realizzare un qualsiasi processo mediante una sequenza ottimale di OU (Biardi G., ed. Città Studi, 2009), in cui occorre che lo studente acquisisca le medesime conoscenze e competenze. Per tale motivo le OU, vengono impartite in un insegnamento a parte, con un metodo “unitario”, che …

SALINITY EFFECTS ON ENZYMATIC BROWNING AND ANTIOXIDANT CAPACITY OF FRESH-CUT BABY ROMAINE LETTUCE (LACTUCA SATIVA L. CV. DUENDE)

Abstract Enzymatic browning is a main problem encountered in minimal processing and further storage of leafy vegetables, leading to shorter shelf-life of products. Changes in the two oxidative activities, polyphenol oxidase (PPO) and peroxidase (POD), as well as in total phenolic content, colour parameters and antioxidant capacity (assayed with ORAC method), were monitored during 10 days of storage at 4 °C of minimally processed baby Romaine lettuce ( Lactuca sativa L. cv. Duende) cultivated under three different salinity conditions (2.8, 3.8 and 4.8 dS m −1 ), in order to determine the most suitable condition for further processing. Increasing levels of salinity reduced both oxidases activ…

Biochemical alterations and quality of ready to eat Opuntia ficus indica L. Miller differently packaged

Innovative enzymatic methods for determining the freshness of the mediterranean crustaceans