Pigment changes during processing of green table olive specialities treated with alkali and without fermentation

Abstract

Green table olive preparations including an alkaline treatment, but not preservation by natural fermentation, such as Castelvetrano-style, are gaining importance in international trade. One of the main highly valued characteristics for this product is a bright green colour, as similar as possible to the fresh fruit. Large proportions of Cu-chlorophyll complexes have been quantified in commercial products of Castelvetrano-style table olives thus in the present work the changes in the chlorophyll and carotenoid composition of olive fruits during this processing style were investigated. The high alkaline pH of the process was the most important feature governing the subsequent transformation of the chlorophyll pigments initially present in the fresh fruit. During processing, the main transformations of pigments were due to allomerization and solvolysis reactions of chlorophylls a and b, which affected the isocyclic ring of the chlorophyll structure but not the Mg atom that remained, and did not change substantially the pigment colour and, consequently, the fruit colour. No Cuchlorophyll derivatives were detected. Then, even though the intense alkali treatment of the olives may cause such damage in the fruit cells that enable contact between the chlorophyll derivatives and the endogenous Cu of the fruit, the absence of acidic conditions during the olive processing did not lead to the previous reaction of Mg replacement by 2H, which is necessary for the following insertion of Cu. With respect to the carotenoid fraction, any noticeable change took place.

Chlorophylls and Carotenoids in Food Products from Olive Tree

“…"s a consequence, the chlorophyll pigments are transformed by solvolysis reactions that afect the isocyclic ring of the chlorophyll structures Figures D and ), such as those that take place during the alkaline treatment of Spanish-style table olives. The absence of a fermentation process for these specialties of table olive does not lead to any acid-catalyzed reactions, and neither Mg-chlorophyll derivatives nor carotenoid isomers with 5,8-furanoid groups is formed [41]. "s a result, this type of table olive is bright green in color, which is one of its most highly valued features.…”

“…The formation of the same Cu chlorophyll complexes, but with endogenous copper of the fruits, has been demonstrated in Spanish-style table olives of the Gordal variety afected by the alteration known as green staining Section 3.2). In the case of Castelvetrano-style table olives, the processing method does not cause the formation of Cu chlorophyll complexes by itself [41]. The intense alkaline treatment of the process provokes a high degree of cell damage in the olive that allows certain level of complexation between chlorophyll derivatives and endogenous copper of the fruit during its shelf life under diferent systems of conservation acid brine, sterilization, and pasteurization), but the amounts formed are not enough to re-green the product [47].…”

Spent cumin seeds generated from ayurvedic industry as a source of bioactive compounds for nutraceutical/functional food applications

“…Data published by Sowbhagya, Florence Suma, Mahadevamma, and Tharanathan () reveal that about 400 metric tons of SC residues are disposed of as waste every year. Value addition of these spent materials by the recovery of bioactive ingredients is gaining lot of importance for the economic sustainability of the related industries and environmental protection point of view (Galanakis, ; Gandul‐Rojas & Gallardo‐Guerrero, ; Martin‐Diana et al, ; Prabhu, Kiran, Sundaresan, Mony, & Venugopalan, ; Uraipong & Zhao, ).…”

Assays to control the development of the green staining alteration in Spanish-style green olives of the Gordal variety

“…The formation of copper (Cu)–chlorophyll complexes with the endogenous Cu of the fruit has been associated with the appearance of GS in Gordal olives fermented following the Spanish style . However, these metal–chlorophyll complexes have also been detected in olives elaborated following the Castelvetrano method and in several samples of commercial table olives …”

“…The formation of copper (Cu)-chlorophyll complexes with the endogenous Cu of the fruit has been associated with the appearance of GS in Gordal olives fermented following the Spanish style. 3 However, these metal-chlorophyll complexes have also been detected in olives elaborated following the Castelvetrano method 4 and in several samples of commercial table olives. 5 It has been proposed that the pectin chain acts as a reservoir of the Cu which forms a complex with chlorophyll derivatives, 6 but the involvement of oxidative disintegration of the fruit chloroplasts is also necessary to allow contact between the chlorophyll pigments and the Cu.…”