1,720,980 research outputs found
Effect of fermentation on the content of bioactive compounds in tofu-type products
No full textTofu is part of Asian cuisine and may be the most popular food made from soy. Due to the influence of processing on some compounds (fatty acids, tocopherols, phospholipids, sterols and phenolic compounds) content of soy food products, soybean flour, traditional tofu and tofu obtained by soymilk fermentation were studied. Fermentation was performed using lactic acid bacteria, such as Lactobacillus casei and Lactobacillus acidophilus. Fermentation by lactic acid bacteria plays an essential role in the reduction of isoflavones glycosides/aglycone ratio (from 0.14 to 0.89 in traditional and fermented tofu, respectively) and in the higher bioavailability of isoflavones, however it does not significantly affect soybean fatty acids and tocopherols. This behaviour suggests the use of these microorganisms to enhance the added value of soybean products, and promote the selection of tailor made starter culture able to growing well in soy milk and contemporary to produce bioactive compounds for specific consumer's categor
Influence of egg products and drying temperatures on egg pasta quality
No full textFoodOmics: Food to Life. The scientific forum where academic and industrial scientists involved in food and nutrition research will discuss about the most recent advances in the “omics” approach
Phenolic compounds in the potato and its byproducts: An overview
Get PDFThe potato (Solanum tuberosum L.) is a tuber that is largely used for food and is a source of different bioactive compounds such as starch, dietary fiber, amino acids, minerals, vitamins, and phenolic compounds. Phenolic compounds are synthetized by the potato plant as a protection response from bacteria, fungi, viruses, and insects. Several works showed that these potato compounds exhibited health-promoting effects in humans. However, the use of the potato in the food industry submits this vegetable to different processes that can alter the phenolic content. Moreover, many of these compounds with high bioactivity are located in the potato’s skin, and so are eliminated as waste. In this review the most recent articles dealing with phenolic compounds in the potato and potato byproducts, along with the effects of harvesting, post-harvest, and technological processes, have been reviewed. Briefly, the phenolic composition, main extraction, and determination methods have been described. In addition, the “alternative” food uses and healthy properties of potato phenolic compounds have been addressed
How Lactobacillus plantarum shapes its transcriptome in response to contrasting habitats
No full textTriplets of Lactobacullus plantarum strains were isolated from nine contrasting habitats. Without any passage through other culture media, isolation and cultivation were on model media that strictly reproduced the chemical and physical conditions and stressors of the habitats of origin. Here, we demonstrated how L. plantarum regulates and shapes its transcriptome in response to contrasting habitats. Firstly, multivariate clustering analysis of transcriptional data (RNA-Seq), complemented with metabolomics and phenomics, grouped the strains according to the habitats of origin. Subsequently, selected strains from each habitat switched to repeated cultivation on MRS medium and transcriptomes homogenized into a unique cluster. Adaptation to this common medium mainly relied on activation of genes for phage- and prophage-related proteins and transposases. Finally, the comparison of growth across model media and with respect to MRS medium showed that 44% of the overall 3112 gene transcripts changed depending on the specific habitat. Regulation and shaping of transcriptomes mainly concerned carbohydrate acquisition, pyruvate catabolism, proteolytic system and amino acid, lipid and inorganic ion transport and metabolism, with contrasting responses for contrasting habitats. Pathways reconstruction demonstrated how the large genome size of L. plantarum imparts transcriptome and metabolic flexibility as the basic mechanism for a nomadic lifestyle
Fermented Nut-Based Vegan Food: Characterization of a Home made Product and Scale-Up to an Industrial Pilot-Scale Production
No full textAbstract: Because of the impossibility to consume food of animal origin, vegan consumers are looking for substitutes that could enrich their diet. Among many substitutes, fermented nut products are made from different nut types and obtained after soaking, grinding, and fermentation. Although other fermented vegetable products have been deeply investigated, there are few data about the fermentative processes of nut-based products and the microbial consortia able to colonize these products are not yet studied. This study characterized a hand-made vegan product obtained from cashew nut. Lactic acid bacteria responsible for fermentation were identified, revealing a succession of hetero- and homo-fermentative species during process. Successively, some lactic acid bacteria isolates from the home-made vegan product were used for a pilot-scale fermentation. The products obtained were characterized and showed features similar to the home-made one, although the microbiological hazards have been prevented through proper and rapid acidification, enhancing their safety features. Practical Application: Spontaneous fermented products are valuable sources of microorganisms that can be used in many food processes as starter cultures. The lactic acid bacteria isolated in this research can be exploited by industries to develop new foods and therefore to enter new markets. The use of selected starter cultures guarantees good organoleptic characteristics and food safety (no growth of pathogens)
Determinazione del contenuto in composti fenolici mediante HPLC-DAD/MS e valutazione dell’attività antiossidante in differenti varietà di patata
No full textLa patata, ampiamente diffusa nell’ alimentazione occidentale, è una ricca fonte di composti fenolici, i quali sono concentrati soprattutto nella buccia. La concentrazione di tali composti bioattivi è strettamente dipendente dalla cultivar, per questo indirizzare la produzione sulla varietà a maggior contenuto fenolico, potrebbe incrementare il valore “nutrizionale” del prodotto finito.
Lo studio condotto nell’ ambito del presente lavoro di tesi si è preposto lo scopo di quantificare e identificare i composti fenolici antiossidanti estratti da sottoprodotti industriali, composti in prevalenza da bucce e da polpa, di diverse varietà di patata, per poterne identificarne le diversità e potenzialità.
Dalla valutazione dell’attività antiossidante degli estratti delle diverse varietà si è potuto desumere un andamento variabile, con anche differenze significative fra alcune varietà. Anche nella determinazione dei fenoli mediante HPLC-DAD/MS si sono riscontrate differenze quantitative fra le varietà. A livello qualitativo, è emerso come la maggior parte dei composti fenolici identificati fossero acidi fenolici, in particolare derivati dell’acido clorogenico e dell’acido ferulico.
Si è voluto, inoltre, verificare la possibile influenza del trattamento con campi elettrici pulsati sull’ attività antiossidante e sul contenuto di fenoli. Il trattamento con PEF, a parità della stessa varietà, non è risultato incidente e non ha significativamente migliorato l’attività antiossidante e il contenuto in composti fenolici dell’estratto analizzato.
Dal presente lavoro di tesi è possibile, quindi, concludere come i sottoprodotti dell’industria pataticola, soprattutto se derivanti da specifiche cultivar di patata, si possano considerare prodotti di interesse e potenziali fonti di antiossidanti naturali a basso costo su cui investire per l’innovazione di nuovi prodotti più salutari e con qualità tecniche e nutrizionali migliori
Functional components and lipid quality assessment in vegetable foods: analytical and technological approaches
No full textLipids are important components that contribute very significantly to nutritional and technological quality of foods because they are the least stable macro-components in foods, due to high susceptibility to oxidation. When rancidity take place, it makes food unhealthy and unacceptable for consumers. Thus, the presence of antioxidants, naturally present of added to foods, is required to enhance shelf life of foods. Moreover, antioxidant like phenolic compounds play an important role in human health enhancing the functionality of foods. The aim of this PhD project was the study of lipid quality and lipid oxidation in different vegetable foods focusing on analytical and technological aspects in order to figure out the effects of lipid composition and bioactive compounds (phenolic compounds, omega-3 fatty acids and dietary fiber) addition on their shelf life. In addition, bioavailability and antioxidant effects of phenolic compounds in human and animals, respectively, were evaluated after consumption of vegetable foods. The first section of the work was focused on the evaluation of lipid quality impact on technological behaviour of vegetable foods. Because of that, cocoa butter with different melting point were evaluated by chromatographic techniques (GC, TLC) and the sample with the higher melting point showed the presence of fatty acids, triglycerides, 2-monoglycerides and FT-IR profile different from genuine cocoa butter, meaning an adding of foreign fat (lauric-fat) not allowed by the law. Looking at lipid quality of other vegetable foods, an accelerated shelf life test (OXITEST®), was used to evaluate of lipid stability to oxidation in tarallini snacks made up using different lipid matrices (sunflower oil, extravirgin olive oil and a blend of extravirgin olive oil and lard). The results showed a good ability of OXITEST® to discriminate between lipid unsaturation and different cooking times, without any samples fat extraction. In the second section, the role of bioactive compounds on cereal based food shelf life was studied in different bakeries by GC, spectrophotometric methods and capillary electrophoresis. It was examined the relationships between phenolic compounds, added with flour, and lipid oxidation of tarallini and frollini. Both products showed an increase in lipid oxidation during storage and antioxidant effects on lipid oxidation were not as expected. Furthermore, the influence of enrichment in polyunsaturated fatty acids on lipid oxidation of pasta was evaluated. The results proved that LC n-3 PUFA were not significantly implicated in the onset of oxidation in spaghetti stored under daylight and accelerated oxidation in a laboratory heater. The importance of phenolic compounds as antioxidant in humans and rats was also studied, by HPLC/MS in the latter section. For this purpose, apigenin and apigenin glycosides excretion was investigated in six women’s urine in a 24 hours study. After a single dose of steamed artichokes, both aglicone and glucuronide metabolites were recovered in 24 h urine. Moreover, the effect of whole grain durum wheat bread and whole grain Kamut® khorasan bread in rats were evaluated. Both cereals were good sources of antioxidants but Kamut® bread fed animals had a better response to stress than wheat durum fed, especially when a sourdough bread was supplied
(Ultra) high pressure homogenization potential on the shelf-life and functionality of kiwifruit juice
Get PDFThe increasing competition within the food industry sector makes the requisite of innovation in processes and products essential, leading to focus the interest on the application of new processing technologies including high pressure homogenization (HPH) and ultra high pressure homogenization (UHPH). In this context, the present research aimed at evaluating the effects of two UHPH treatments performed at 200 MPa for 2 and 3 cycles on quality and functionality of organic kiwifruit juice stored at three different temperatures, i.e., 5, 15, and 25°C. The results showed that only the treatment performed at 200 MPa for 3 cycles was able to significantly increase the shelf-life of organic kiwifruit juices when stored at refrigeration temperature, avoiding also phase separation that occurred in the sample treated at 0.1 MPa (control) after 20 days of refrigerated storage. The obtained data showed also that the highest applied pressure was able to increase some quality parameters of the juice such as viscosity and luminosity (L∗) and increased the availability of total phenol content consequently enhancing the juice total antioxidant activity. The application of a treatment at 200 MPa for 3 cycles allowed to obtain a stable kiwifruit juice for more than 40 days under refrigerated storage. A challenge to implement this technology in food process as full alternative to thermal treatment could be represented by the adoption of pressure level up to 400 MPa followed by the packaging in aseptic conditions
Phenolic composition as measured by liquid chromatography/mass spectrometry and biological properties of Tunisian barley
No full textIn this work, phenolic composition, antioxidant and antibacterial activities of selected Tunisian barley varieties were studied. Swihli barley exhibited the highest total phenolic content and the strongest antioxidant and antibacterial activities. Liquid chromatography/mass spectrometry analysis revealed significant qualitative and quantitative differences in phenolic composition among the different varieties. Procyanidin B3 and catechin were the most abundant. Pearson’s correlation test revealed significant correlations between the antioxidant activities of barley extracts and both hydroferuloyl glucose and catechin-3-glucose
Studio di shelf life tramite confezionamento in atmosfera modificata di mango, papaya e ananas disidratati.
No full textIl presente elaborato è nato da un'esperienza di ‘tirocinio per tesi’ svolta presso l’azienda ravennate Eurocompany S.r.l. Il progetto ha avuto come cardine una problematica, sollevata dall’azienda, legata a prodotti tropicali disidratati quali papaya, ananas e mango che presentavano uno scadimento qualitativo precoce durante la shelf-life.
La metodologia di confezionamento utilizzata dall’azienda comprendeva un film in poliaccoppiato a media barriera, con successiva foratura del film. Questa ‘precauzione’ viene normalmente utilizzata dall’azienda per scongiurare eventuali rigonfiamenti dovuti a possibili sviluppi microbici.
Lo scopo della tesi è stato quello di provare una nuova soluzione di confezionamento, per valutare un possibile effetto positivo sui prodotti. Nello specifico, è stato utilizzato lo stesso film, non forato, confezionando in atmosfera protettiva (70% N2, 30% CO2). Il contenuto di CO2 è stato giustificato dalla letteratura, dove tale gas è indicato come antimicrobico, mentre N2 ha normalmente la funzione di gas riempitivo. Durante i 4 mesi della sperimentazione, le confezioni dei tre prodotti sono state mantenute a temperature di 30-35 °C ed umidità relativa tra il 50-60%. Ogni 20 giorni, per un totale 7 punti di prelievo (t0-t6), si è proceduto a effettuare le seguenti analisi:
- Misurazione della variazione dell’atmosfera interna alla confezione;
- Misura dell’umidità con il metodo in stufa;
- Misura dell’attività dell’acqua tramite Aqualab;
- Confronto di immagini ottenute tramite fotocamera in camera oscura;
- Analisi sensoriale (su campioni a fine shelf-life).
La sperimentazione ha mostrato, sui tre prodotti, un parziale effetto positivo del nuovo condizionamento applicato. D’altro canto, è emerso che l’utilizzo di un film non in grado di filtrare i raggi UV ed a media barriera per il vapore d’acqua e ossigeno comporta un evitabile decadimento qualitativo derivante dalle reazioni chimiche generate dai gas permeanti il film (O2 e vapore d’acqua)
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