Ultrasound in Olive Oil Extraction

Each olive oil extraction system should combine the best product quality and the highest efficiency. At the same time, the innovative technologies can develop only if they provide sustainable processes. To reach these goals, academic and industrial researchers need to understand the key elements that allow to modulate the events that occur during oil extraction. In the past years, many emerging technologies, that is techniques perceived as capable of changing the present situation, have been developed. Among these, ultrasounds applications seem to be the most promising for their mechanical and slightly thermal effects, without affecting sustainability. In order to explain the maturity of this emerging technology, the main effects of the ultrasounds application in the olive oil extraction process are discussed, the developed plants are presented, and the patents are reported

Sensory and Biochemical Characterization of Novel Drinks Based on Tomato Juice

In these last years, consumers’ choices are being directed towards healthier food and beverages with an increasing demand for functional products. In this study, we investigated the sensory and biochemical properties of novel drinks based on tomato juice. To this purpose, different blends were formulated mixing fresh tomato juice with other fruit juices and nectars in different proportions and then assayed to investigate their sensory (panel test), compositional and biochemical characteristics. Our results indicated that it is possible to formulate tasty drinks based on tomato juice with improved nutritional properties. The combinations of red fruits/tomato (60/40 v/v) and red fruits/orange/tomato (40/30/30 v/v/v) showed a sugar content lower than those of different soft drinks on the market including energy drinks, and suitable lycopene levels as well. Interestingly, the blended red fruits/orange/tomato had a greater number of polyphenols and vitamin C, a softer tomato flavour and high sensory appreciation. High pasteurization (90ºC,7 min), performed to increase storability, did not significantly affect sensory and biochemical properties of drinks. These achievements may be useful to modulate tomato flavour release and consumer acceptability of novel drinks based on tomato juice

Estimating the Cost of Wave Energy Converters at an Early Design Stage: A Bottom-Up Approach

The role of ocean energy is expected to grow rapidly in the coming years, and techno-economic analysis will play a crucial role. Nowadays, despite strong assumptions, the vast majority of studies model costs using a top-down approach (the TdA) that leads to an unrepresentative economic model. WEC developers usually go through the the TdA approach because more detailed cost data are not available at an earlier design stage. At a very advanced design stage, some studies have also proposed techno-economic optimisation based on the bottom-up approach (BuA). This entails that the detailed cost metrics presented in the literature are very specific to the WEC type (hence not applicable to other cases) or unrepresentative. This lack of easily accessible detailed cost functions in the current state of the art leads to ineffective optimisations at an earlier stage of WEC development. In this paper, a BuA for WECs is proposed that can be used for techno-economic optimisation at the early design stage. To achieve this goal, cost functions of most common components in the WEC field are retrieved from the literature, exposed, and critically compared. The large number of components considered allows the results of this work to be applied to a vast pool of WECs. The novelty of the presented cost functions is their parameterization with respect to the technological specifications, which already enables their adoption in the design optimisation phase. With the goal of quantifying the results and critically discuss the differences between the TdA and the BuA, the developed methodology and cost functions are applied to a case study and specifically adopted for the calculation of the capital cost of PeWEC (pendulum wave energy converter). In addition, a hybrid approach (HyA) is presented and discussed as an intermediate approach between the TdA and the BdA. Results are compared in terms of capital expenditure (CapEx) and pie cost distribution: the impact of adopting different cost metrics is discussed, highlighting the role that reliable cost functions can have on early stage technology development. This paper proposes more than 50 cost functions for WEC components. Referring to the case study, it is shown that while the total cost differs only slightly (11%), the pie distribution changes by up to 22%. Mooring system and power take-off are the cost items where the TdA and the HyA differ more from the BuA cost estimate

Effect of Salt Addition and Fermentation Time on Phenolics, Microbial Dynamics, Volatile Organic Compounds, and Sensory Properties of the PDO Table Olives of Gaeta (Italy)

‘Oliva di Gaeta’ is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the ‘Itrana’ method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of ‘Oliva di Gaeta’. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more “Sour” and “Bitter” taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more “Fruity” notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the ‘Itrana’ method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of ‘Oliva di Gaeta’

Microwave and Ultrasound-Assisted Extraction of Capsaicinoids From Chili Peppers (Capsicum annuum L.) in Flavored Olive Oil

The extraction of flavoring compounds from different plants and aromatic herbs has been using since ancient times in vegetable oils to enhance their aroma and taste, whereas the technology of production has changed over time. Our work aimed to evaluate alternative technologies for the production of aromatized olive oil such as ultrasound- and microwave-assisted extraction in comparison to traditional infusion or maceration of dried red hot chili pepper (10% w/v for 7 days). For the ultrasonic treatment, samples of olive oil were prepared by adding 10% and 20% dried chili pepper and subjected to ultrasound-extraction for 10 or 20 minutes. For microwave extraction, samples were added with 20% chili powder and treated for 10, 30 or 60 seconds. Capsaicinoids were quantified by HPLC-DAD directly in the flavored olive oil and antioxidant activity was evaluated by ABTS+ method. Capsaicinoids analysis in aromatized olive oil treated 20 minutes by ultrasound resulted about 130 ppm (capsaicin and hydroxycapsaicin), when 10% chili powder was used, while it was 250 ppm when 20% chili was used. The content of capsaicinoids extracted by traditional infusion was always higher for both concentrations of chili powder studied. The concentration of capsaicinoids in samples treated by microwaves extraction seem to be dependent on the treatment time, resulting 130 and 230 ppm capsaicinoids for 10 and 60 seconds of treatment, respectively. In conclusion, the production of flavored olive oils by using technologies such as microwave and ultrasound-extraction could allow the production of high quality oils, with fast and cost-effectively methods

Biophenolic Compounds Influence the In-Mouth Perceived Intensity of Virgin Olive Oil Flavours and Off-Flavours.

In this study, the influence of phenolic compounds on the sensory scores attributed to extra virgin olive oil (EVOO) by panel test was investigated. Two model olive oils (MOOs) with identical concentrations of volatile compounds, differing only in the amount of biophenols (297 vs. 511 mg kg−1), were analysed by two official panels and by SPME-GC/MS. Six other MOOs set up by the two previous models were also tested and analysed. They were formulated separately with the addition of three off-flavours (‘rancid’, ‘winey–vinegary’ and ‘fusty–muddy’). While high levels of EVOO phenolic compounds did not produce any effect on the headspace concentration of volatile compounds, they did affect the scores of both positive and negative sensory attributes of EVOO, due to the well-known in-mouth interactions between EVOO phenols, saliva and volatile compounds. In particular, a decrease of about 39% in the positive fruity score was found in the presence of a higher concentration of phenols. Regarding EVOO off-flavours, the higher level of phenolic compounds decreased by about 23% the score of ‘fusty–muddy’ defect and increased the score of ‘winey–vinegary’ defect about 733%. No important effect of EVOO phenolics on the perceived intensity of the ‘rancid’ defect was found. These findings could be helpful in explaining some discrepancies of panel test responses observed during extra virgin olive oil shelf life

Industrial-scale filtration affects volatile compounds in extra virgin olive oil cv. Ravece

Extra virgin olive oil (EVOO) cv. Ravece (Campania region, Italy) was studied to investigate the effects of the industrial filtration process on the legal quality parameters, fatty acids, phenolics, and volatile compounds. Filtration did not cause significant changes in some quality indices, i.e., acidity and spectrophotometric indices, with the exception of K232 value. Peroxide value was significantly higher after the filtration process, probably due to further exposure to oxygen. This increasemay affect oil shelf life. The content of total phenolic compounds did not change dramatically, but hydroxytyrosol and 3,4-DHPEA-EA were significantly lower in filtered oil, arising from complex biophenols hydrolysis. Little but significant changes were also observed for some fatty acids. The majority of 38 volatile compounds analyzed by the SPME-GC/MS technique did not change significantly (p0.05) after industrial filtration, while some of them increased their initial concentration up to twofold, i.e., 2-methylbutanal. 6-Methyl-5-hepten-2-one and heptanol also increased after filtration, while t,t-2,4-hexadienal, t-2-hexen-1-ol, and c-2-penten-1-ol significantly decreased