The relationship between olive paste malaxation temperature and the concentration of olive oil hydrophilic phenols (HP), i.e. simple phenols, secoiridoids and lignans, was investigated. Malaxation ...experiments were performed at laboratory scale for 45 min at 21, 24, 27, 30, 33 and 36 °C. A significant (p <0.05) increment of total phenols concentration was found with a maximum at 27 °C, whereas for higher temperatures (30-36 °C) a progressive decrement was observed. A similar pattern was recorded approximately for all the secoiridoid compounds, i.e. a quasi-linear increment of concentrations with increasing temperature until 30 °C, followed by a marked decrease in correspondence with the higher malaxation temperature (33 and 36 °C). The amount of simple phenols increased linearly with increasing temperature and no decrements were observed up to the maximal temperature investigated (36 °C), while no significant differences were found for lignans. A small increment of peroxide values and total chlorophyll was recorded as a function of the increasing malaxation temperature, whereas no differences were observed in the free acidity. The results highlight that there is not a univocal relationship between HP concentration and malaxation temperature. An equilibrium between degradation (chemical and biochemical oxidation and hydrolysis) and transfer (partitioning) phenomena was hypothesized.
The influence of the olive oil processing steps paste malaxation (PM), decanter centrifugation (DC), and vertical centrifugation (VC) on the dissolved oxygen (DO) concentration in virgin olive oil ...(VOO) right after production was investigated at industrial plant scale for two successive years. The influence of this parameter on quality decay during shelf life, assessed by peroxide value (PV) analysis, was also monitored. The VC step showed the higher oxygenation effect (50% increase in comparison to the control), and a good linear regression (r² = 0.83) was found between the initial DO concentration and the PV after 2 days. An 18-months shelf life test, performed on VOO sampled before and after the VC, indicated the slowest decay kinetics in the oils with the lower initial DO concentration, i.e. the non-centrifuged oils.
Precoat-bodyfeed filtration of virgin olive oil was investigated on an industrial filter-press plant. Several chemical parameters of the unfiltered oil were measured and the relationship with ...filtration performances was investigated by Principal Component Analysis. Further, Linear Discriminant Analysis was applied to develop a predictive model for oil filterability. Principal Component Analysis allowed the construction of latent variables which were used to separate oil groups and to select variables for Linear Discriminant Analysis. The developed linear model gave an overall correct recognition of about 88%, good enough for a convenient filterability prediction of oil at industrial scale.
Power demand of a flail shredder during the harvest of pineapple fields Pérez de Corcho Fuentes, Jorge S(Universidad de Ciego de _vila Facultad de Ingeniería); Garbati Pegna, Francesco(Universitá di Firenze Dipartimento de Ingegneria Agraria e Foréstale); Iglesias Coronel, Ciro(Universidad Agraria de La Habana Centro de Mecanización Agropecuaria) ...
Ciencia e investigación agraria,
04/2009, Volume:
36, Issue:
1
Journal Article
Peer reviewed
Open access
The power demand of the demolition of pineapple (Ananas comosus) fields, whose production cycle is finished with a flail mower with two different knives, a cutting apparatus with three angular ...velocities, and a tractor with three translation velocities, was determined using strain gage measures. The results of the investigations demónstrate the influence of the knife type and cinematic regime of the cutting apparatus in the demand of energy in the pineapple demolition. Furthermore, they permitted the validation of models of the power demand of the flail mower.
Se determinó la demanda de potencia de la demolición de campos de pifia (Ananas comosus) que terminan su ciclo de producción con una trituradora de mayales, con dos tipos de cuchillas, tres velocidades angulares del órgano de corte y tres velocidades del conjunto, utilizando mediciones tensométricas. Los resultados de las investigaciones demuestran la influencia del tipo de cuchilla y el régimen cinemático del órgano de corte en la demanda de energía en la demolición de rastrojos de pifia, y permitieron validar los modelos para la demanda de potencia de la trituradora.
The effect of blanketing with CO2, naturally evolved during malaxation of olive pastes, on the quality of virgin olive oil was investigated at lab‐scale. The O2 depletion was monitored along with CO2 ...emission to confirm the previously hypothesized accelerated respiration. Malaxation experiments were conducted for 180 min both in sealed (SC) and in the traditional open‐to‐air conditions to ascertain whether the oil quality was affected by O2 concentration as afforded by CO2 blanketing. The quality of olive oils obtained at different time intervals was monitored by total acidity, peroxide value (PV), specific extinction coefficients K232 and K270, total chlorophyll and total hydrophilic phenols, and HPLC hydrophilic phenols profile. A rapid decrease in oxygen concentration and a simultaneous increase in CO2 concentration were recorded, confirming the accelerated respiration. The oil produced in SC showed a lower PV and K232 coefficient and a higher chlorophyll (10–17 mg/kg) and hydrophilic phenols (110 mg/kg) concentration. No differences in total acidity and K270 coefficient were observed. The hydrophilic phenols profile indicated that, at least for the Frantoio cultivar and an advanced ripeness state, the maximal extraction is generally achieved already after 20 min. Most of the individual hydrophilic phenols have higher concentrations (up to 50%) in SC.
A method is presented for the assessment of operational risk from the use of sprayers based on environmental impact analysis. The method expresses the risk as a sum of possible negative outcomes on ...the environment and the operator, considering the effects of a set of factors relating to pesticide applications. Risk assessment has been carried out for the more representative types of sprayers, highlighting the advantages that can be obtained through technological improvements and operational constraints. The method allows a risk to be associated with each sprayer so that a risk classification may be expressed.
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