Alfredo Montaño

Utilization at high pH of starter cultures of lactobacilli for Spanish-style green olive fermentation.

Inoculation at alkaline pH (above 9) of lye-treated green olives with starter cultures of Lactobacillus pentosus CECT 5138 was studied. Despite an initial loss of viability in the order of 1-2 log cycles on average, depending mainly on time of application, cultures grew and initiated an accelerated fermentation process. Inoculation reduced the population of Enterobacteriaceae, and thereby potential spoilage, and produced a quicker acidification of brines and decrease of pH, when compared with control uninoculated batches. Results obtained throughout three consecutive seasons demonstrated that utilization at high pH of starter cultures of lactobacilli is feasible, provided that the inoculum size takes into account the initial low survival.

Chemical profile of industrially fermented green olives of different varieties

Over 160 fermented brines, from green olives of Manzanilla, Hojiblanca, and Gordal varieties processed in five companies in two consecutive seasons, were analysed for physicochemical characteristics, organic acids, sugars, and volatile components. The composition of the brine following fermentation was assumed to be identical to that of the aqueous phase of the olives. Olive variety and processor were found to have a greater influence than season on both physicochemical characteristics and chemical composition. Hojiblanca olives presented values of pH, combined acidity, and volatile acidity significantly (P<0.05) higher than those of Manzanilla and Gordal, reflecting different processing conditions. The volatile/total acidity ratio, which did not differ between varieties or seasons, appeared to correlate with development of the “fourth stage” of fermentation. The major compounds were lactic, acetic, succinic and formic acids, ethanol, and methanol, with the contents of ethanol and formic acid being significantly different in all three varieties. Residual fermentation substrates, such as mannitol, glucose, sucrose, and citric acid, in addition to propanol, propionic acid, 2-butanol, and acetaldehyde, were found in low concentrations.

Lactic acid fermentation and storage of blanched garlic

The controlled fermentation of peeled, blanched garlic, using a starter culture of Lactobacillus plantarum, was studied and compared with that of unblanched garlic. Blanching was carried out in hot water (90 degrees C) for 15 min. The starter grew abundantly in the case of blanched garlic, producing mainly lactic acid and reaching a pH of 3.8 after 7 days, but its growth was inhibited in unblanched garlic. Ethanol and fructose, coming from enzymatic activities of the garlic, and a green pigment were formed during the fermentation of unblanched garlic, but not of blanched garlic. The blanched garlic fermented by L. plantarum, even without a preservation treatment (pasteurization), was microbiologically stable during storage at 30 degrees C in an acidified brine (approximately 3% (w/w) NaCl and pH 3.5 at equilibrium), but fructans were hydrolyzed. The packed fermented product and that obtained by direct packing without fermentation were not significantly different with regard to flavour.

Analysis of zapatera olives by gas and high-performance liquid chromatography

Abstract Gas chromatography and high-performance liquid chromatography were applied to normal and “zapatera” olive brines obtained from typical fermentation brines of green table olives after different treatments. The zapatera samples were obtained by pH adjustment to 5.1 followed by inoculation with a suspension of sediment from a zapatera brine and incubation at 30°C for 40 days. The compounds determined were lactic acid, C 2 -C 6 fatty acids, acetaldehyde, methanol, ethanol, 2-butanol and n -propanol. Normal and zapatera brines were compared to identify components that indicated spoilage. One of these components was found in the gas chromatogram of the volatile fatty acids from the zapatera samples and identified as cyclohexanecarboxylic acid by gas chromatography-mass spectrometry. A comparison of the corresponding aromagrams revealed quantitative differences in aroma composition. Various relationships calculated from the peak areas of selected unknown components in these aromagrams were so distinct as to provide a basis for characterizing zapatera spoilage.

Table Olives: Varieties and Variations

Publisher Summary Table olives are the products prepared from sound fruits of the cultivated olive tree. Table olive production was initially restricted to the producing regions, mainly around the Mediterranean Sea. Today, however, olive preparation has extended to both North and South America, and even Australia. A characteristic common to almost all olive varieties is their extreme bitterness when tasted fresh. The glucoside oleuropein is responsible for this, and the different processing methods are aimed at removing this compound in order to obtain fruits with more-palatable attributes. It could be said that there are as many processing methods as places where olives are consumed. In an attempt to normalize the different products, the International Olive Council has a Trade Standard Applying to Table Olives, in which the types, trade preparations, quality factors, and other properties are described. This chapter aims to describe in detail the different kinds or classifications applicable to table olives, explaining the distinctive traits for each case.

Influence of processing conditions on acrylamide content in black ripe olives.

The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.

Note: Quantification of Ascorbic Acid and Dehydroascorbic Acid in Fresh Olives and in Commercial Presentations of Table Olives

Ascorbic acid (AA) and dehydroascorbic acid (DHAA) were determined by high performance liquid chromatography (HPLC) in fresh green olives as well as a diversity of commercial presentations of table olives (based on both Spanish-style green olives and directly brined olives). Fresh green olives (Manzanilla cv.) immediately after harvest contained about 9mg total ascorbic acid/100g f.w., with DHAA representing more than 90% of this amount. During the post-harvest period (till 2 weeks) the total vitamin C remained stable when olives were stored at 6°C, but significant degradation occurred at ambient temperature (~35% loss after 7 days). In commercial presentations of table olives, in general, the main contribution to the total vitamin C level appeared to come from AA added as an antioxidant, the maximum level being found in Manzanilla olives stuffed with anchovy streams (36.1mg/100g f.w.). However, in some samples (e.g. plain olives) that did declare any added AA, very low levels (0.1-0.6mg total AA/100g f.w.) were found. Our hypothesis is that, in those samples, AA would be degraded by lactic acid bacteria and/or yeast from olive fermentation, whereas pasteurisation in other presentations (e.g. stuffed olives) would stabilise added AA.

Effect of processing and storage time on the contents of organosulfur compounds in pickled blanched garlic.

The influence of processing, with and without fermentation, on the contents of organosulfur compounds, namely, γ-glutamyl peptides, S-alk(en)yl-L-cysteine sulfoxides (ACSOs), and S-allyl-L-cysteine (SAC), in pickled blanched garlic was evaluated. For each processing type, the effect of the preservation method and storage time was also analyzed. Blanching in hot water (90 °C for 5 min) hardly affected the individual organosulfur compound content. The fermentation and packing steps negatively affected the levels of all compounds except for SAC. The content of this compound increased during storage at room temperature whereas γ-glutamyl peptides and ACSOs were degraded to various extents. The pasteurization treatment itself had no significant effect on the concentrations of organosulfur compounds. Use of the corresponding fermentation brine in the case of the fermented product in conjunction with refrigerated storage was found to be the best method to preserve the levels of organosulfur compounds in pickled garlic stored for up to one year.

Determination of benzoic and sorbic acids in packaged vegetable products. Comparative evaluation of methods

Three analytical methods for determining sorbic and benzoic acids in various packaged vegetable products were evaluated, with special attention being paid to green olives. Two of these methods used a simple, isocratic, reversed-phase HPLC technique for separating and detecting the preservatives, but differed in the preparation of the sample (extraction with 60% methanol or steam distillation). The third method was based on separation by steam distillation and determination of the acids in the distillate by spectrophotometry. For the olives, while this method proved to be excellent (total error < 25%) for high concentrations (> 100 ppm), the HPLC methods were more efficient for the whole range of concentrations studied (5-500 ppm). Both HPLC methods had detection limits of approximately 1 ppm for the two preservatives. With other sample matrices (tomatoes, cucumbers, caperberries, silver-skinned onions and hot peppers), the three methods proved to be excellent for high concentrations of preservatives (500 ppm), but at low levels (20 ppm), the spectrophotometric method and the HPLC method with extraction by 60% methanol proved to be unacceptable (total error > 50%) in some cases.

Fibre fraction carbohydrates in Olea europaea (Gordal and Manzanilla var.)

Abstract Olive dietary fibre, Gordal and Manzanilla varieties, has been isolated by chemical (acid and neutral detergent fibre of Van Soest) and enzymatic (soluble and insoluble fibre of Asp) methods. NDF and ADF values were lower than IF. All of the fractions were hydrolysed and the resultant neutral sugars quantified. Glucose was the main component in NDF, ADF and IF, and arabinose was the major one in SF. The content of protein was significantly different between fractions but not between varieties, and the content of cellulose was significantly different between fractions and varieties. The determination of hemicelluloses by the Van Soest method showed a very low precision (cv. > 40%); determined by acid hydrolysis there were significant differences between fractions and varieties.