Antonio Higinio Sánchez

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.

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.

Identification of European Hake Species (Merluccius merluccius) Using Real-Time PCR

A rapid and precise method for identifying European hake (Merluccius merluccius) based on TaqMan technology is presented. The method can be applied to fresh, frozen, and processed fish products to detect the fraudulent or unintentional mislabeling of this species. Specific primers and a minor groove binding (MGB) TaqMan probe were designed for this purpose based on partial sequences of the mitochondrial DNA control region. Combinations of primers and probe concentrations that gave the lowest Ct value and the highest final fluorescence value were selected to carry out efficiency, specificity, and cross-reactivity assays. The method was successfully tested on 31 commercial hake samples. A Ct value of about 16 was obtained when Merluccius merluccius was present; however, the fluorescence signal was not detected most of the time (Ct value 40) or presented significantly higher Ct values (38.2 +/- 0.96) for the nonhake species.

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.

Chemical Composition of Fermented Green Olives: Acidity, Salt, Moisture, Fat, Protein, Ash, Fiber, Sugar, and Polyphenol

Publisher Summary Of fermented green olives, alkali-treated green olives in brine, also known as “Spanish-style green olives” or “pickled green olives,” are the most widely distributed and investigated type of table olive. However, there are other traditional preparations of fermented green olives which are of lesser economic importance in the international market, but highly appreciated by consumers in the Mediterranean region. One of these involves the direct brining of green olives without prior de-bittering with NaOH solution. This preparation is known as “untreated green olives in brine,” “naturally green olives,” “directly brined olives,” or “Sicilian-style green olives.” The taste of untreated green olives is completely different from that of alkali-treated fruits, mainly due to the residual bitterness they retain even after a long period of storage in brine. This olive type (green or turning-color) is one of the bases for many other commercial products, such as “seasoned” olives, which are very popular in Spain. When this preparation is made with natural black olives, it is known as Greek-style table olives, and has been extensively studied. This chapter reviews the two processing types of fermented green olive—that is, Spanish-style and untreated (green or turning-color) olives—with special emphasis on the characteristics (physicochemical parameters, chemical composition) of the final product. It presents a summary of information in the literature regarding the major components in the fresh fruit (raw material).

Processing and storage of lye-treated carrots fermented by a mixed starter culture

A mixed culture of Lactobacillus plantarum and Saccharomyces cerevisiae was compared with a single culture of L. plantarum as starter for the fermentation of lye-treated carrots. Using the mixed culture, more than 95% of glucose, fructose and malic acid was consumed after 7 days of fermentation in a brine containing 2.5% w/v NaCl and 0.7% acetic acid, but only 54% of sucrose was degraded. The fermentation products quantified were lactic acid, ethanol and acetic acid and carbon recovery was 88%. Using the single culture of L. plantarum, substrate consumption was lower, and carbon recovery almost 100%. In uninoculated lye-treated carrots, heterofermentative bacteria grew, with the production of considerable amounts of mannitol. In all cases, the stability, sensorial characteristics and carotenoid content of the packed product were studied during 9 months of storage at 30 degrees C, and two different preservation systems were compared: addition of preservatives, approximately 500 and 1000 mg/kg of sorbic and benzoic acid, respectively, and pasteurization at 80 degrees C for 10 min. The pasteurized samples were microbiologically stable during the storage period, while lactic acid bacteria grew in the samples with preservatives. Storage time significantly (P < 0.05) affected the texture and colour parameters (L*, a*, b*) of the carrots, but not the amounts of alpha- and beta-carotene. The type of fermentation had no significant effect on texture, colour parameters or carotenoid content. The preservation method had no significant effect on texture or carotenoid content, but did affect colour (parameter a*). The flavour of carrots fermented by the mixed culture was significantly (P < 0.05) preferred to that of those fermented with a single culture of L. plantarum.

Fermented vegetables containing benzoic and ascorbic acids as additives: benzene formation during storage and impact of additives on quality parameters.

Chemical and sensorial changes related to the use of benzoates and ascorbic acid as additives in packed fermented vegetables were investigated. For this, three selected vegetables (green olives, cucumbers, and caperberries) stored under different conditions (glass or plastic containers, ambient or refrigerated storage) were used. In all cases, benzoic acid remained unchanged (glass bottle) or decreased slightly (plastic pouch) at prolonged storage. Ascorbic acid was partially or totally degraded during storage, the degradation rate depending on the storage conditions and the vegetable matrix. Benzene levels higher than 10 μg/L were found in cucumbers and caperberries containing both additives, but only when packed in plastic pouches and after prolonged storage at room temperature. In these conditions, an appreciable browning of brine, related to AA degradation, was also found. The use of benzoate alone had a significant influence on vegetable color, but flavor was not significantly affected at the benzoate levels tested. On the basis of the present study, benzoates should be removed from fermented vegetable formulations containing ascorbic acid to eliminate possible benzene formation during long-term storage.

Comparative study of the use of sarcosine, proline and glycine as acrylamide inhibitors in ripe olive processing

The main purpose of this study was to evaluate the inhibitory effect on acrylamide (AA) formation and the impact on sensory characteristics in ripe olives of three selected amino acids (sarcosine, proline and glycine), which previously showed high AA inhibition rates in an olive model system. Each amino acid was separately added to packing solutions to give 100 or 200 mM at equilibrium, prior to a sterilisation treatment at 121°C. The results showed that sarcosine at 100 mM may be a good candidate for reducing the AA content in ripe olives with a limited effect on sensory characteristics. Studies with a model solution of AA and sarcosine heated at 121°C for 30 min suggested that the main mechanism for the inhibitory effect of sarcosine on AA formation was the Michael reaction. Graphical Abstract

Combined use of nitrogen and coatings to improve the quality of mechanically harvested Manzanilla olives.

The combined effect of an edible coating and a nitrogen atmosphere on the quality of Manzanilla olives mechanically harvested and processed as Spanish-style green olives was assessed. The percentage of olives free of any brown spots ranged between 35-50%, 10-25% and 50-65% for fruit directly processed, storage under nitrogen and coated and storage under nitrogen respectively. Moreover, olives stored in the open air developed brown spots due to the oxidation of oleuropein. By contrast, the anoxic conditions prevented oleuropein from undergoing enzymatic oxidation but not from its enzymatic hydrolysis. Hence, the phenolic derivative HyEDA was formed in olives stored under nitrogen, and this substance was rapidly oxidized in the open air to give rise to brown spots although to a lesser extent in the coated fruit. Therefore, the postharvest storage of coated olives under nitrogen can be a good method to prevent bruise damage in mechanically harvested fruit.