Effects of irrigation treatments on the quality of table olives produced with the Greek-style process

A Review on Adventitious Lactic Acid Bacteria from Table Olives

Spontaneous fermentation constitutes the basis of the chief natural method of processing of table olives, where autochthonous strains of lactic acid bacteria (LAB) play a dominant role. A thorough literature search has unfolded 197 reports worldwide, published in the last two decades, that indicate an increasing interest in table olive-borne LAB, especially in Mediterranean countries. This review attempted to extract extra information from such a large body of work, namely, in terms of correlations between LAB strains isolated, manufacture processes, olive types, and geographical regions. Spain produces mostly green olives by Spanish-style treatment, whereas Italy and Greece produce mainly green and black olives, respectively, by both natural and Spanish-style. More than 40 species belonging to nine genera of LAB have been described; the genus most often cited is Lactobacillus, with L. plantarum and L. pentosus as most frequent species—irrespective of country, processing method, or olive type. Certain LAB species are typically associated with cultivar, e.g., Lactobacillus parafarraginis with Spanish Manzanilla, or L. paraplantarum with Greek Kalamata and Conservolea, Portuguese Galega, and Italian Tonda di Cagliari. Despite the potential of native LAB to serve as starter cultures, extensive research and development efforts are still needed before this becomes a commercial reality in table olive fermentation.

Volatile Composition, Sensory Profile and Consumer Acceptability of HydroSOStainable Table Olives

HydroSOStainable table olives (cultivar Manzanilla) are produced from olive trees grown under regulated deficit irrigation (RDI) strategies. Olives produced by RDI are known to have a higher content of some bioactive compounds (e.g. polyphenols), but no information about consumer acceptance (or liking) have been reported so far. In this study, the volatile composition, the sensory profile and the consumer opinion and willingness to pay (at three locations) for HydroSOStainable table olives produced from three RDI treatments and a control were studied. Volatile composition was affected by RDI, by increasing alcohols, ketones and phenolic compounds in some treatments, while others led to a decrease in esters and the content of organic acids. Descriptive sensory analysis (10 panelists) showed an increase of green-olive flavor with a decrease of bitterness in the HydroSOStainable samples. Consumers (study done with 100 consumers in 2-rural and 1-urban locations; n_total = 300), after being informed about the HydroSOStainable concept, preferred HydroSOStainable table olives to the conventional samples and were willing to pay a higher price for them (52% 1.35–1.75 € and 32% 1.75–2.50 € as compared to the regular price of 1.25 € for a 200 g bag). Finally, green-olive flavor, hardness, crunchiness, bitterness, sweetness and saltiness were defined as the attributes driving consumer acceptance of HydroSOStainable table olives.

Effect of Spanish-style processing on the quality attributes of HydroSOStainable green olives

BACKGROUND

Three treatments of regulated deficit irrigation (RDI) were assayed on olive trees for table olive production. RDI provides hydroSOStainable crops. The effect of RDI treatments on the quality of raw and table olives was determined based on their: weight, pit weight, fruit/pit ratio, size, texture, colour, mineral content, antioxidant activity, total phenol content and organic acid and sugar profile.

RESULTS

HydroSOStainable olives showed the most attractive shape and colour: highest fruit weight, roundest fruit, hardest texture and a lightest and greenest colour than control olives. Minerals, antioxidants, phenols and organic acids and sugars of hydroSOStainable olives were similar to control olives. After processing to table olives, calcium, potassium, antioxidants and phenols contents decreased, whereas sugars and organic acids profiles changed in both types of olives.

CONCLUSIONS

HydroSOStainable table olives offer environmental and quality advantages over control olives given the reduced use of fresh water and favourable morphological traits, which are more attractive for consumers. © 2018 Society of Chemical Industry.

Energy and environmental performances of hybrid photovoltaic irrigation systems in Mediterranean intensive and super-intensive olive orchards

Over the last decades, traditional olive production has been converted to intensive and super-intensive cultivation systems, characterized by high plant density and irrigation. Although this conversion improves product quality and quantity, it requires a larger amount of energy input. The new contributions in this paper are, first, an analysis of the energy and environmental performance of two commercial-scale high peak-power hybrid photovoltaic irrigation systems (HPVIS) installed at intensive and super-intensive Mediterranean olive orchards; second, an analysis of PV hybrid solutions, comparing PV hybridization with the electric power grid and with diesel generators; and finally, a comparison of the environmental benefits of HPVIS with conventional power sources. Energy and environmental performances were assessed through energy and carbon payback times (EPBT and CPBT). The results show EPBT of 1.98 and 4.58 years and CPBT of 1.86 and 9.16 years for HPVIS in Morocco and Portugal, respectively. Moreover, the HPVIS were able to achieve low emission rates, corresponding to 48 and 103 g CO₂e per kWh generated. The EPBT and CPBT obtained in this study were directly linked with the irrigation schedules of the olive orchards; therefore, weather conditions and irrigation management may modify the energy and environmental performances of HPVIS. The consumption of grid electricity and diesel fuel, before and after the implementation of HPVIS, was also analyzed. The results obtained show fossil energy savings of 67% for the Moroccan farm and 41% for the Portuguese installation. These savings suggest that the energy produced by HPVIS in olive orchards will avoid the emissions of a large amount of greenhouse gas and the exploitation of natural resources associated with fossil fuel production.

Approaches to improve the growth of the starter lactic acid bacterium OM13 during the early stages of green Spanish-style table olive production

The present research aimed at determining the optimal conditions for the lactic acid fermentation of green Spanish-style table olives. The work is a follow-up, and focuses on the performance of the commercial starter strain Lactobacillus pentosus OM13 by applying an acclimatization step and the addition of nutrients, and concentrations of lactic acid that were previously investigated. The acclimatization of the cells warranted the dominance of the starter culture even at an inoculation level of 2 Log cycles lower than that commonly used in standard fermentation. A significant effect was found in terms of acidification kinetics within the first week of fermentation, with the highest decrease in pH, at ~2.5 units, which occurred in the trial and after inoculation with 106 CFU/mL of starter after acclimatation (EO3) that showed values similar to control C obtained with Lactobacillus pentosus OM13 at a concentration of 107 CFU/mL. After day 3, further decreases in pH of up to 4.30 were observed until day 30, and then these values remained almost constant until the end of process (day 190) when lower pH values were reached for trial EO3 and control C. The results of microbiological dynamics, the changes in VOCs and finally the effect of the processes on the sensory analysis of the fermented product were investigated by multivariate analysis. The acclimatization process and the initial inoculation level influenced the bacterial microflora, aromatic compounds and organoleptic characteristics of the final product. Finally, the trials C, EO2 and EO3 showed higher values (60-80%) of preferences and satisfaction compared to other experimental productions.