1. New operating conditions to increase quality
and sustainability of olive oil production chain
Marzia Migliorini1, Chiara Cherubini1, Lorenzo Cecchi1, Giacomo Gianni1, Serena Trapani2 and Bruno Zanoni2
1 - Metropoli - Special Agency of the Chamber of Commerce of Florence - Chemical Laboratory Division; Florence –Italy
2 - Dept. Agricultural Biotechnology, University of Florence; Florence- Italy
Introduction
The quality of extra virgin olive oil (EVOO) can be evaluated not only by estimating its product parameters, which are determined by current applicable regulations, but also by assessing its phenolic and aromatic compound content. The quality and types of phenolic and aromatic compounds contained in extra virgin olive oil is dependent upon both chemical composition of processed olives and operating conditions for processing in olive oil mill. The quality of extra virgin olive oil is determined by a series of chemical and enzymatic changes, which occur during the extraction process (Di Giovacchino et al., 2002). Literature studies have shown that olive oil quality can be improved by controlling and addressing the phenomena of oil synthesis and transformation throughout the oil production chain (Migliorini et al., 2009).
This work was carried out within the two-year project “Misura 124” for PSR , promoted and coordinated by Regione Toscana, published in BURT of Regione Toscana no. 7 of , entitled “Validazione di protocolli per la produzione di oli di oliva ad elevato valore nutrizionale ed a ridotto impatto ambientale. Acronimo OLEOSALUSISTEM.” Results from the first year’s activity are reported below.
ACIDITY
(% oleic acid)
Olive health condition
Process time-temperature
EVOO filtration
Legal
Quality
EVOO storage conditions (time, O2, light,..)
Process operating conditions (times, temperatures, O2 exposures)
PEROXIDE VALUE
(mEq O2/kg oil)
UV adsorption
(K232; K270;ΔK)
EVOO storage conditions (time, O2, light,…)
Process operating conditions (times, temperatures, O2 exposures)
Olive cultivar
Olive health condition
Process operating conditions
EVOO storage conditions
Phenolic compound
content (PCc)
PCc means:
Antioxidants for oil shelf-life
Antioxidants for human health
Oil bitterness and pungency
Business
Quality
Aim of the work
The aim of this work was to install an innovative extraction system, based on the concept of reduced-oxidative-stress. In addition, some new technologies were designed to use by-products obtained from oil extraction. EVOOs produced by this system were compared with EVOOs from Tuscany region during the same crop season.
Olive cultivar
Olive health condition
Process operating conditions
EVOO storage conditions
Volatile compound
content (VCc)
VCc means:
Oil aroma and flavour
Results
Oil samples obtained were compared with average oil products from the same crop season in Florence (Italy) for chemical parameters of quality indicators (acidity, peroxide value, UV in table 1, phenolic compound in table 2, and aromatic compound in table 3).
Table 1. Acidity, Peroxide and UV value for reg.2568/91 , Oleosalusistem and Crop season 2011
Table 2. Phenolic compound value (mg/kg) for Oleosalusistem and Crop season 2011.
Table 3. Volatile compounds derived from “LOX pathway” (mg/kg) for Oleosalusistem and Selezione regionale.
Table 4. %Defects for Oleosalusistem and Selezione regionale.
Materials and methods
Experimental design
During crop season, several batches of approx. 200 kg olives from Frantoio and Moraiolo cultivars were processed in an oil mill (Azienda Agricola Buonamici, Fiesole, Florence, Italy).
Plant for oil extraction (TEM, Florence, Italy) consisted of a cleaning and water washing system, an olive grinding cutter crusher (mod. FR350), a controlled-temperature vertical axis malaxation equipment (500 kg capacity) (mod. V500), a decanter (two-step mod. D1500 ) with 1500 kg/h maximum capacity and a cardboard filter press (15 μm cut-off).
Olives were processed within 12 h from harvest at two ripening dates: 16th November 2011 and 23rd November Oil extraction trials were carried out in quadruple.
Olives were crashed at 2500 rpm with holes of 6.5 mm diameter; malaxation was carried out at half capacity under vacuum (residual pressure of 20 kPa) at 22 ± 1°C for a mean value of 15 min; decanter worked with a screw conveyor rotating at a slower speed than that of the bowl.
The process step relating to sustainable recycling of plastic residue, or “alperujo”, was only planned during the first year of research project (Fig. 1).
Figure 1. Extraction process.
Chemical analyses
Olive oil samples obtained were subjected to chemical analyses: Fig. 2 shows analyses performed and gives a brief description of the information that can be obtained from analysis results. Acidity (% oleic acid), peroxide value (meq O2/kg-1) and spectroscopic indices were measured according to EU official method (Anonymous, 1991). Extraction, identification and determination of phenolic compounds were performed in agreement with IOC Official Method (Anonymous, 2009). The volatile compound content was determined in agreement with the method described by Vichi et al. (2005), using the HS-SPME-GC-MS technique (i.e. solid phase microextraction of the headspace coupled with a gas chromatograph having a mass spectrometer as a detector).
Oleosalusistem
Reg. n. 2568/91
Analyses
Maximum allowable value
Acidity
≤ 0.8
Peroxide value
≤ 20
K232
≤ 2.50
K270
≤ 0.22 ΔK
≤ 0.01
Min value
Max value
Avg value
0.19
0.27
0.22
1.80
6.2
4.5
1.63
1.90
1.79
0.15
0.18
0.16
-0.01
- 0.01
Acidity
Peroxide value
K232
K 270
Δ K
Sample No.
446
362
278
Min value
0,09
1,8
1,29
0,08
-0,05
Max value
0,94
19,1
2,86
0,23
0,01
Average value
0,22
6,5
1,81
0,14
0,00
Crop Season
2011
Oleosalusistem
Crop Season 2011
Sample No. 19
Min value
448
Max value
787
Average value
662
Sample No.
257
Min value
139
Max value
952
Average value
491
Selezione Regionale
Oleosalusistem
Sample No. 59
Min value
11,82
Max value
35,76
Average value
18,43
Sample No. 19
Min value
10,40
Max value
15,39
Average value
12,80
Selezione Regionale
Oleosalusistem
Total sample No. 19
Defected sample No. 6
% Defective samples
31-36
Total sample No.
135
Defected sample No. 76
% Defective samples 56
Conclusions
Based on result analysis, it can be concluded that oil obtained from Oleosalusistem experiments showed following differences, when compared to other oil produced in Tuscany region:
1. Definitely lower legal quality parameters;
2. A 25 % increase in phenolic compounds;
3. A 30 % decrease in volatile compounds;
4. A definitely lower percentage of defective samples.
References
Di Giovacchino L, Sestili S and Di Vincenzo D,. Inluence of olive processing on virgin olive oil quality. European Journal of Lipid Science and Technology 104, (2002).
Migliorini M, Cheubini C, Zanoni B, Mugelli M, Cini E, Berti A,. Influence of operating conditions of malaxation on the quality of extra virgin olive oil. Riv. Ital. Sostanze Grasse LXXXVI, (2009).
Anonymous, Regulation (EC) n Official Journal EC 248, 6-35 (1991).
Anonymous, COI, T20. Doc n.29 (2009).
Vichi S, Piazzale L, Conte L. S, Buxaredas S, L’opez-Tamames E.Simultaneus determination of volatile and semi-volatile aromatic hydrocarbons in virgin oil by headspace solid-phase microextraction coupled to gas chromatography/mass spectrometry. Journal Chromatography 1090, (2005).
10th Euro Fed Lipid Congress, September 2012, Cracow Poland
The research leading to these results has received funding from “Bando Misura 124” of PSR of Regione Toscana, promoted and coordinated by Gal - Start srl, published on the BURT of Regione Toscana n. 7 of 16 J 2011 for the project Oleosalusistem: “Validazione di protocolli per la produzione di oli ad elevato valore nutrizionale ed a ridotto impatto ambientale”