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Microbiota and metabolome of un-started and started Greek-type fermentation of Bella di Cerignola table olives
Get PDFThis study aimed to utilize an “omics” approach to evaluate the ability of selected lactobacilli and yeasts to improve the fermentation process of Bella di Cerignola table olives. Four types of fermentations were performed at the pilot-plant scale: un-started fermented olives used as a control (Ctrl); olives started with a commercial Lactobacillus plantarum strain (S); commercial L. plantarum strain and autochthonous yeast Wickeramomyces anomalus DiSSPA73 (SY); and L. plantarum, W. anomalus DiSSPA73, autochthonous L. plantarum DiSSPA1A7 and Lactobacillus pentosus DiSSPA7 (SYL). Compared to Ctrl, S, SY, SYL showed a higher acidification (P < 0.05) of the brine, which reached a pH value of 4.49 after one day of fermentation. The microbiota of unfermented olives and brine after one day of fermentation was primarily composed of Enterobacteria that belonged to Hafnia alvei and Methylobacterium. However, L. plantarum and L. pentosus dominated the total and metabolically active microbiota of the Ctrl brines and olives at the end of the fermentation. The use of lactobacilli and W. anomalus DiSSPA73 as a starter culture markedly affected the microbiota of the brines after one day of fermentation. The number of species (OTU) and the results of an alpha diversity analysis indicated that the microbial diversity of the brines was markedly simplified by the S, SY and, in particular, SYL fermentations. According to the lowest biodiversity, S, SY and SYL samples showed the lowest abundance of Proteobacteria, including Enterobacteriacea, Lactococcus lactis, Propionibacterium acidipropionici and Clostridium. The lactobacilli and W. anomalus DiSSPA73 used in this study markedly affected the amounts of free amino acids, phenolic and volatile organic compounds. Both a texture profile analysis and a sensory evaluation showed the highest appreciation for all of the started table olives. As shown through microbiological, biochemical, and sensory analyses, an accelerated fermentation of Bella di Cerignola table olives was achieved using the selected lactobacilli and yeast strains
Sviluppo di burger a base di legumi
No full textLe leguminose, dopo i cereali, rappresentano le colture alimentari più diffuse nel mondo e, in un futuro che prevedrà un forte incremento della popolazione mondiale, esse giocheranno un importante ruolo nella nutrizione umana in quanto fonte di proteine a basso costo. In considerazione delle esigenze dei consumatori moderni, che richiedono alimenti caratterizzati da elevata praticità d’uso e buone caratteristiche sensoriali, è nata l’idea di formulare, produrre e caratterizzare da un punto di vista chimico e nutrizionale, un burger precotto a base di legumi. La preliminare valutazione sensoriale ha evidenziato il positivo apprezzamento per il burger prodotto, con punteggi medi superiori
a 6,5 per tutti i descrittori esaminati e con differenze che risultavano legate soprattutto all’età dei consumatori. Da un punto di vista chimico e nutrizionale, il burger era caratterizzato da un elevato contenuto in fibre e da un profilo in acidi grassi ed aminoacidi in linea con le più recenti linee guida per una sana e corretta alimentazione. Infine, il contenuto medio percentuale di fibre (pari a 6,4%) era sufficiente per poter applicare, secondo la vigente normativa, il claim nutrizionale “ad alto contenuto di fibre
Evolution of the oxidative stability, bio-active compounds and color characteristics of non-thermally treated vegetable pâtés during frozen storage
No full textBACKGROUND
Few studies have investigated the effects of frozen storage on processed vegetables. The present study evaluates its effects on the quality characteristics of non‐thermally stabilized tomato‐based pâtés compared to thermally stabilized pâtés stored at room temperature. Two different types of tomato‐based pâtés were analyzed in terms of bio‐active compounds, as well as colorimetric parameters and oxidative degradation just after processing and also after 4, 8 and 12 months of storage.
RESULTS
Thermal treatment mainly affected the colorimetric parameters and oxidative degradation, whereas its effects on bio‐active compounds became more visible and significant during storage. Freezing allowed in both pâtés to maintain significantly higher a* values than storage at room temperature, whereas brightness, which is linked to residual activities of different enzymes, varied during storage according to the ingredient formulation. During storage, oxidative degradation of the lipid fraction was more marked in the pâté containing a lower quality oil, and less marked when the absence of thermal treatment was combined with frozen storage.
CONCLUSION
Freezing could represent a viable alternative way to preserve high‐quality products over time. An optimal combination of blanching, freezing rate, storage and thawing conditions will provide the best results in terms of the quality/price ratio. © 2017 Society of Chemical Industr
Combined effects of a natural Allium spp. extract and modified atmospheres packaging on shelf life extension of olive-based paste
No full textThis study aimed to extend the shelf life of non-thermally stabilised olive-based paste by adding different concentrations (0.2, 0.5, 1.0 g kg−1) of a natural Allium spp. extract and/or by using different packaging atmospheres (MAP1, 75% Ar-23% CO2-2% H2; MAP2, 70% N2-30% CO2) during refrigerated storage. Higher amounts of the natural extract gave the highest level of microbial inhibition, increased hardness, a greater release of aldehydes, esters, and ketones, and a better colour preservation when used with MAP1. The natural extract and MAP, either alone or in combination, produced no sensory defects (except for the control in MAP2), but a greater loss of typical olive flavour. The addition of the natural extract used with an appropriate MAP, can retain the quality attributes and extend shelf life for approximately 14 days longer than the control (without natural extract and MAP), and a better performance is achieved by using greater amounts of natural extract and MAP1
Use of starter cultures for table olives fermentation as possibility to improve the quality of thermally stabilized olive-based paste
No full textThe objective of this work was to improve the quality of thermally stabilized olive-based paste (ObP), obtained from table olives fermented with different starter cultures. Four different trials were performed: conventional fermentation by indigenous bacteria and yeasts (Treatment 1); fermentation using commercial Lactobacillus plantarum as starter (Treatment 2); fermentation using commercial L. plantarum and selected autochthonous yeast Wickerhamomyces anomalus DiSSPA73 (Treatment 3); fermentation using commercial L. plantarum, W. anomalus DiSSPA73, L. plantarum DiSSPA1A7, and Lactobacillus pentosus DiSSPA7 (Treatment 4) on which microbiological, physicochemical, and sensory analyses were carried out. The results showed no significant influence of starter cultures on colorimetric indices. From the olives fermented using yeasts, both with and without association of selected lactic bacteria, we obtained an olive-based paste richer in phenol compounds, carotenoids, and free amino acids, which had a better volatile and sensory profile, characterized by lower amounts of the volatile compounds associable to sensory defects
Use of olive leaf extract to reduce lipid oxidation of baked snacks
No full textOlive leaves are a waste of the olive oil processing industry and represent a good source of phenolic compounds. The aim of this work was to assess the influence of olive leaf extract (OLE) on lipid oxidation of baked snacks, like breadsticks, made with wheat flour, extra virgin olive oil (EVO), white wine, and salt. Two EVOs having different peroxide value and antioxidant profile (total phenol content, tocopherols, carotenoids, and antioxidant activity) were considered. The snacks were subjected to oven test or stored in the usual conditions of retailer shelves. The obtained data highlighted that EVO plays a key role both for the quality and for the shelf-life of baked snacks and the use of OLE is recommended especially when baked snacks are produced with low quality EVO which therefore does not have a good content of natural antioxidants. The OLE addition significantly reduced the forced oxidative degradation during oven test, as evidenced by a decrease of 27% in oxidation-related volatile compounds and of 42% in triacylglycerol oligopolymers compared to control snacks (CTR) without OLE. Moreover, OLE effectively acted also in normal storage conditions, improving sensory data, induction times, antioxidant activity, and volatile compounds compared to CTR (i.e. hexanal 165.49 vs 38.31 μg g−1in OLE-added). The amount of oxidation-related volatile compounds showed an opposite trend with the quality level of oil used
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