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Biotechnological valorisation of residues and by-products from agro-food industries ! Valorizzazione biotecnologica di residui e sottoprodotti dell’industria agro-alimentare
No full textSome of the activities of my PhD thesis project are described. The chemical characterization of food by-products (i.e. pomegranate and citrus residues and Equisetum arvense) such as their phenolic content and volatile profile was carried out; these results were related with their functional activities as the antimicrobial and the antioxidant ones. The most promising by-products were used as ingredients directly added to a food, i.e. ‘Primo Sale’ cheese.In questo documento sono descritte alcune delle attività del mio progetto di tesi di dottorato. In, particolare, è stata effettuata la caratterizzazione chimica di alcuni sottoprodotti alimentari (residui di melograno e agrumi e Equisetum arvense) quali il contenuto fenolico ed il profilo in molecole volatili; questi risultati sono stati messi in relazione con le loro attività funzionali (antimicrobica e antiossidante). I sottoprodotti più promettenti sono stati utilizzati come ingrediente aggiunto direttamente ad un alimento: il formaggio "Primo Sale"
Valorisation of olive pomace and tomato by-products with selected yeasts strains
No full textFood industries produce high amounts of by-products, wastes and residues which are considered a problem because they contribute to environmental pollution. On the other hand, by-products are generally rich in various nutrients and functional compounds, e.g., dietary fibres and/or bioactive components such as flavonoids and polyphenols recognized as antimicrobial and anti-radical compounds. A possible strategy for their valorization is their use as feedstock for microbial fermentation by selected strains of yeast and lactic acid bacteria (LAB) for the production of valuable bio-based compounds. In particular, in this study olive pomace (OP) and tomato residues and seeds (TR) were analyzed, and 31 strains of yeasts were isolated from OP and 30 from TR. In addition, more than 50 strains of LAB were isolated from TR. Yeasts were characterized for some metabolic features such as lipase, protease and beta-glucosidase activities. When grown in culture media with OP or TR as the only nutrient source, marked lipolytic and proteolytic activities were shown by some yeast strains already after 2 days of incubation at 30°C. Moreover, more than 60 volatile compounds interesting for the food, cosmetics or chemical sectors were detected by GC/MS-SPME analysis. In particular, several molecules used as food flavouring or perfume compounds were identified. In conclusion, the results obtained indicate that the tested biotechnological approach can be a promising strategy for the exploitation of polluting by-products through the production of bio based flavours. From a technological point of view, the yeast isolates could be also exploited for bioremediation of olive oil wastewaters or as a source of enzymes of biotechnological interest
Valorization of agri-food by-products as functional ingredients for soft cheeses.
No full textHuge amounts of by-products and wastes are yearly generated by the food processing industry all over the world. While several issues are related to their management and disposal due to their environmental impact, numerous investigations are carried out aiming at their valorization through the extraction of valuable components or the production of bio-based products, e.g. for the food, feed, chemical or nutraceutical sectors. In general vegetable residues and byproducts are sources of micro- and macro-nutrients, bioactive compounds, e.g. antioxidants and antimicrobials, and dietary fibres which have recognised beneficial effects on human health. Furthermore, they may be characterised by some relevant technological properties, e.g. water binding and gelling capacity, which overall make them as potential functional ingredients. In this study some food by-products, i.e. citrus and pomegranate residues, chitin, chitosan and horsetail (Equisetum arvense), were initially screened for some desired properties for their use as functional food ingredients, i.e. antimicrobial activity against some food-borne pathogens, prebiotic activity, ability to support the growth of lactic acid bacteria (LAB) used as starters for food fermentations or probiotics. Based on the results, the most promising ones were selected and used as ingredients for a functional soft cheese added with probiotic LAB. Overall, results showed that growth over refrigerated storage of spoilage psychrotropic population was slower in cheeses with added the agri-food by-products than in control ones, while viability of probiotic LAB was unaffected by the added ingredients. Moreover, the antioxidant activity and the profile in volatile compounds were improved resulting in higher acceptability and taste as assessed by a preliminary panel test thus confirming the potentials of the agri-food by-products to be used as
multi-functional ingredient
Use of electrolysed water in sprouts production to control microbial contamination.
No full textReady-to-eat sprouted seeds are widely consumed in Europe because they are convenient and an important source of micro- and micro-nutrients. The production process of the sprouts requires the seeds to be kept in water up to 4-5 days in the presence of high humidity (95%) and a temperature between 22-28°C. These conditions are however suitable for the proliferation of the microbiota on the surface of the seeds, and their levels can vary from 102
to 106 CFU/g. The microbiota is generally represented by yeasts, Pseudomonadaceae, lactic acid bacteria, spore-forming bacteria and enterobacteria, and pathogens may also be present. At the end of the production process, the sprouts have very high cell load levels which can reach values up to 108 CFU/g. This results in both high microbiological risks, as evidenced also by the European recent cases of toxic infection associated with their consumption, and a very short product shelf-life (3-5 days).
Electrolyzed water (EW) is an emerging technology with potential applications in various sectors including food and agriculture. EW has strong bactericidal properties comparable to traditional sanitizers such as sodium hypochlorite, with the advantages to be safer.
In this context, the objective of this work was to evaluate the effectiveness of EW to reduce
microbial contamination of Daikon seeds during 48 hours sprouting. In particular, microbial load of the sprouted seeds using EW was compared to those obtained with tap water or sodium hypochlorite solutions. Furthermore, the possible reduction in the microbial population of the sprouts following washes with EW or sodium hypochlorite for times between 5 and 30 minutes was verified.
Results on the use of EW for the sprouting phase showed that contamination levels were about 1.5-2 logarithmic cycles lower than seeds sprouted with tap water. Moreover, no detectable differences in the color and length of the sprouts were observed. On the other hand, sodium hypochlorite, which is the reference sanitizer, showed a higher efficacy than EW against mesophilic and psychrotrophic bacteria, while its activity against Enterobacteriaceae was the same as EW.
An important aspect from the application point of view was to evaluate the effects of changing the EW during the sprouting process. Water changes every 6-8 hours improved the microbiological quality of the sprouted seeds. The contamination levels for mesophilic and psychrotrophic bacteria (4-6 log CFU/g) and enterobacteria (2-4 log CFU/g) were lower than sprouts obtained with the same EW solution for 48 hours. This result suggests the importance of maintaining adequate levels of active chlorine to ensure its action during the whole sprouting process. Concerning the sanitization washes of the sprouts before their distribution, results showed that EW has a much higher efficacy than the reference sanitizer (sodium hypochlorite) against mesophilic and psychrotrophyc bacteria
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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