Bvps codes for solving optimal control problems

Optimal control problems arise in many applications and need suitable numerical methods to obtain a solution. The indirect methods are an interesting class of methods based on the Pontrya-gin’s minimum principle that generates Hamiltonian Boundary Value Problems (BVPs). In this paper, we review some general-purpose codes for the solution of BVPs and we show their efficiency in solving some challenging optimal control problems

Biotecnologie applicate alla valorizzazione della \u201cPagnotta di Piana degli Albanesi\u201d

Il presente articolo riassume il progetto di valorizzazione della Pagnotta di Piana degli Albanesi attraverso lo sviluppo di un impasto acido ottenuto da batteri lattici selezionati dalle materie prime, al fine di legare la produzione al territorio e permettere di recuperare le note di tipicit\ue0. Le farine e le semole rappresentano dei veri e propri habitat microbici, la cui composizione pu\uf2 variare in funzione dell\u2019area geografica e delle condizioni di conservazione. Trattandosi di materie prime che non possono essere trattate termicamente prima della trasformazione, esse trasferiscono i loro microrganismi al prodotto in lavorazione. Pertanto, qualora tali microorganismi esprimano propriet\ue0 panarie rappresentano degli utili strumenti per l\u2019esaltazione delle note aromatiche desiderate. Il contributo scientifico riporta le popolazioni lattiche delle materie prime siciliane impiegate nella produzione di pani tipici, la selezione dei batteri lattici e lo scaleup della loro applicazione

Effect of different salting technologies on the chemical and microbiological characteristics of PDO Pecorino Siciliano cheese

The present work was carried out to evaluate the effect of two salting technologies [dry salting (DS) and the combined dry-brine salting (DBS)] on the chemicophysical and microbiological characteristics of PDO Pecorino Siciliano cheeses of different final weight (6 and 12 kg). Dry matter was significantly influenced by both salting process and final size. Twelve kilogram cheeses treated by DBS showed higher protein content with higher soluble nitrogen per cent than 6 kg cheeses. Salt content was in the range 3.1–4.0% on dry matter. The colour did not show significant differences for any of the factors, but 12 kg cheeses subjected to DS showed higher yellow index than the other cheeses. The resistance at 30% of strain was influenced by cheese size, with 6 kg cheeses showing higher resistances than 12 kg cheeses. All cheeses were dominated by coccus LAB, but pseudomonads and Enterobacteriaceae showed comparable levels of about 105 cfu/g. Significant microbiological differences were evidenced only for enterococci and yeasts concerning the final cheese size. Thirteen species of LAB, belonging to five genera (Enterococcus, Lactobacillus, Lactococcus, Pediococcus and Streptococcus), were identified, but several spoilage/ pathogenic species were also identified, especially Pseudomonas putida, Citrobacter freundii and Stenotrophomonas maltophilia. LAB isolates were preliminary evaluated for their physiological characteristics in view of developing autochthonous starters to improve the microbiological quality of PDO Pecorino Siciliano cheese

Effect of Mucilage-Based Edible Coating Enriched with Oregano Essential Oil on Postharvest Quality and Sensorial Attributes of Fresh-Cut Loquat

Due to pulp browning, weight loss, firmness loss, and decay, loquat fruits, and even more minimally processed fruits have a very short post-harvest life. The aim of our study was to evaluate the effect of Opuntia ficus-indica mucilage-based edible coating enriched with oregano oil on postharvest quality, microbial growth, and sensorial attributes of fresh-cut cv Martorana loquat fruit during cold storage. Fresh-cut loquat fruits were dipped in the mucilage-based solution enriched with oregano essential oil (MO-EC) and in distilled water used as control (CTR). According to our results, the mucilage-based edible coating enriched with oregano oil significantly improved the postharvest life of minimally processed loquat fruits by preserving quality, nutraceutical value, and sensory aspects. MO-EC had a barrier effect on fresh-cut loquat fruit, reducing weight and firmness losses, inhibiting TSS, TA, ascorbic acid content decrease, and enhancing the antioxidant activity until the end of the cold storage period (11 days at 5 C). Microbiological analysis revealed that coated loquat fruits were characterized by a cell density of spoilage microorganisms 1 Log cycle lower than control fruits. The mucilage-based coating enriched with OEO positively affects the visual appearance of fresh-cut loquat fruits, at the end of the cold storage period, MO-EC samples did indeed report visual ratings that were five times greater than CTR samples. Our research suggests that applying mucilage-based coating enriched with OEO improves peeled loquat fruit shelf-life and allows the producers to sell products that are usually considered unmarketable (fruit with epicarp with large spot areas) to the market

Microbial Safety of Black Summer Truffle Collected from Sicily and Umbria Regions, Italy

Background: Tuber aestivum Vittad., known as black summer truffle, represents high-value food especially used as garnishment in nouvelle cuisine. The aim of this study was to investigate on the viable microbial populations associated with T. aestivum ascomata collected in different sites of Sicily and one locality of Umbria (Italy). Methods: The ripe ascomata of black summer truffles were collected from Central Italy. Cell densities of spoilage bacteria, fecal indicators, potential pathogens, yeasts, and molds were analyzed. Statistical analysis was conducted with XLSTAT software. Results: The microbiological counts of truffles ranged between 6.00 and 9.63 log Colony Forming Unit (CFU)/g for total mesophilic count and between 6.18 and 8.55 log CFU/g for total psychrotrophic count; pseudomonads were in the range 6.98-9.28 log CFU/g. Listeria spp. and coagulase-positive streptococci detected in no samples. Coagulasenegative streptococci were found in some samples with 2.11-4.76 log CFU/g levels. Yeasts and filamentous fungi were detected at consistent levels of 3.60-7.81 log CFU/g. Significant differences (p<0.01) were found between samples and also for all microbial groups. Conclusion: This study evidenced that the common brushing procedure applied for preparation of truffles is not sufficient to eliminate microbial risks for consumers. The application of an efficient decontamination treatment is strongly suggested before consumption of fresh truffles

Effect of Opuntia ficus-indica Mucilage Edible Coating in Combination with Ascorbic Acid, on Strawberry Fruit Quality during Cold Storage

Strawberry fruit is a nonclimacteric fruit and is one of the most consumed berries in the world. It is characterized by high levels of vitamin C, folate, vitamin E, β-carotene, and phenolic constituents as well asanthocyanins that are strictly related to health benefits. Strawberries are highly perishable fruit with a very short postharvest life due to their susceptibility to mechanical injury, rapid texture softening, physiological disorders, and infection caused by several pathogens (yeast and mold) that can rapidly reduce fruit quality. The aim of the present study was to evaluate the effect of the application of Opuntia ficus-indica mucilage in combination with ascorbic acid, as edible coating, on quality, sensorial parameters, and microbiological characteristics of strawberry fruit during cold storage at 4 ± 0.5°C and 85% RH. Strawberries were characterized by a linear increase of weight loss during the storage at 4°C that was significantly higher (+11.3% on average) in the uncoated strawberries. The coating affected the ascorbic acid content of the strawberries that increased by 36.0% in coated strawberries; total soluble solid content and color of the strawberries were only affected by storage. Visual quality and sensorial analysis recorded higher scores in the coated samples at the end of the cold storage period. Furthermore, the mucilage coating did not negatively affect the natural taste of strawberries. The application of O. ficus-indica gel-based edible coating in combination with ascorbic acid, although not able to inhibit the microbial growth, limited significantly their development in coated strawberry fruits. Our results suggest that Opuntia mucilage plus 5% ascorbic acid could be a useful biochemical way of maintaining strawberry fruit quality and extending their postharvest life

EFFECTS OF CITRUS ESSENTIAL OILS ON THE MICROBIOLOGICAL SAFETY OF PRIMO SALE CHEESE

In the last years, the consumers demanding foods with no chemical preservatives for food conservation, determined an interest by the food industries for the use of natural biopreservatives. Several essential oils from various plants and fruits have been characterized for their antibacterial activities in order to select new biopreservatives. The aim of this work was to evaluate the organoleptic effect of citrus essential oils to be applied in the processing of sheeps’ milk “Primo Sale” cheese and the inhibitory effect on the main bacterial pathogens of dairy interest. In order to better evaluate the antibacterial effect, the first approach was based on pasteurized milk, in view of the future application in raw milk cheese production. Three industrial citrus essential oils (EOs) extracted by cold pressing of the citrus peels were tested: Orange [Citrus sinensis (L.) Osbeck] Lemon [Citrus limon (L.) Osbeck] and Tangerine [Citrus reticulata Blanco]; sheep bulk milk was pasteurized for 30 min at 60°C. Each EO was tested at two different concentrations 100 and 200 µl/l of milk. For each dose two cheese makings were made: one production was not added with pathogenic bacteria to evaluate the organoleptic characteristics, while the second production was added with 30 CFU/mL of Listeria monocytogenes 24B0 and Salmonella typhimurium 50431 and 103 CFU/mL of Escherichia coli C45/1245 and Staphylococcus aureus PSS52. All cheeses were obtained by coagulation with 0.3 mL/L of microbial rennet (Fromase® 220 TL, DSM Bright Science Brighter Living, Heerlen, UK) and acidification by means of the starter culture Lactococcus lactis CAG4 and CAG37 10 mL/L to reach a final concentration of 106 CFU/ml in milk. Four cheese makings without EOs were used as control trials and prepared as follows: only rennet; rennet plus pathogenic bacteria; rennet plus starters; and rennet plus pathogenic and starters. Cheese samples were homogenised with a stomacher (BagMixer® 400, Interscience, Saint Nom, France). Microbial suspensions were plated and incubated as follows: Lactic acid bacteria cocci on M17 agar, incubated anaerobically at 30°C for 48 h; L. monocytogenes on Listeria selective agar base incubated at 37°C for 48 h; Escherichia coli and S. typhimurium were both detected on Hektoen enteric agar incubated at 37°C for 24 h; St. aureus on Baird Parker and incubated at 37°C for 48 h. Although in vitro tests showed a certain inhibition against especially, the Gram positive bacteria, but also towards Salmonella spp. none of the two Gram negative pathogens was inhibited in cheeses. Optimal results were registered against L. monocytogenes which was inhibited of almost 3 Log cycles by all EOs at both concentrations tested. St. aureus was not inhibited by orange EO, while 1-2 Log cycles lower than control (only pathogens) were found in EO cheeses. The inhibitory effect could also be due to the competitions for nutrients due to the most rapid growth of Lc. lactis. However, the difference registered among orange and the other two citrus EO trials highlighted the in vivo antibacterial activity of lemon and mandarin EOs. Sensory tests are being prepared to evaluate the appreciation by judges