NEW BASIC AND APPLIED STRATEGIES FOR THE STABILIZATION OF GREEN COLOR IN TABLE OLIVES

Project information
"A. SUMMARY OF THE PROPOSAL THE PROPOSED CHALLENGE SEEKS TO IMPROVE A SECTOR OF GREAT IMPORTANCE IN THE NATIONAL AGRO-FOOD INDUSTRY, HELPING TO SOLVE THE TECHNICAL PROBLEM OF PRESERVING GREEN COLOR IN SPECIALTIES OF TABLE OLIVES, A SPANISH PRODUCT LEADING THE INTERNATIONAL MARKETS AND WITH HIGH IMPACT IN ANDALUSIA. TAKING INTO ACCOUNT THAT THE CHLOROPHYLL PROFILE OF THE OLIVE FRUIT IS ESSENTIAL IN DEVELOPING A STRATEGY TO ADDRESS THE STABILIZATION OF GREEN IN TABLE OLIVES, IT IS NECESSARY TO KNOW IN DEPTH AND DETAIL THE MECHANISM THAT LEADS TO A SPECIFIC CHLOROPHYLL COMPOSITION. ALTHOUGH GREAT ADVANCES HAVE BEEN MADE IN THE ESTABLISHMENT OF THE CHLOROPHYLL CATABOLIC PATHWAY, SUCH RESEARCH HAS BEEN DEVELOPED DURING LEAF SENESCENCE AND ASSUMING FULL PARALLELISM DURING FRUIT RIPENING. HOWEVER, RECENT ADVANCES IN THE IDENTIFICATION OF FINAL CHLOROPHYLL CATABOLITES, AS WELL AS THE SPECIFIC DEGRADATIVE ENZYMES, HAVE REVEALED SIGNIFICANT DIFFERENCES IN THE CHLOROPHYLL CATABOLIC PATHWAY DURING LEAF SENESCENCE AND FRUIT RIPENING. THEREFORE, ONE OF THE OBJECTIVES OF THIS PROJECT IS TO STUDY AND ESTABLISH AT ANALYTICAL, BIOCHEMICAL AND MOLECULAR LEVEL THE METABOLIC REACTIONS WHICH ARE PRESENT IN THE OLIVE FRUIT. ON THE ONE HAND, WE WILL ADVANCE IN THE BASIC KNOWLEDGE OF THE CHLOROPHYLL CATABOLISM IN FRUITS, AND ON THE OTHER HAND WE AIM TO IDENTIFY NEW COLORLESS CATABOLITES WITH HIGH ABILITY FOR ZN(II)-BINDING THIS KNOWLEDGE WILL HELP TO ESTABLISH NEW STRATEGIES THAT STABILIZE THE COLOR OF THE PROCESSED OLIVE FRUIT. RESULTS FROM THE CURRENT PROJECT AGL2012-39714 SHOW THAT THE USE OF THE FOOD ADDITIVE E-650 (ZINC ACETATE) ALLOWS TO GET A FAST GREEN COLOR IN TABLE OLIVES TREATED WITH ALKALI. THE COLORED CHLOROPHYLL DERIVATIVES COMPLEXED WITH ZINC (ZN-CLS) INVOLVED IN THE RE-GREENING EFFECT HAVE BEEN IDENTIFIED, AND THE BEST REACTION CONDITIONS TO ACCELERATE THEIR FORMATION HAVE BEEN SET. THIS PROPOSAL SEEKS TO INCREASE THESE SCIENTIFIC AND TECHNOLOGICAL KNOWLEDGE, CARRYING OUT NEW RESEARCH ACTIVITIES SPECIFICALLY FOCUSED TO THE OPTIMIZATION OF THE PROCESS, INCLUDING THERMAL TREATMENTS THAT ARE NEEDED TO ENSURE THE PRODUCT SAFETY IN THE LONG TERM. THE AIM IS TO MINIMIZE THE ZN (II) CONTENT OF THE FINAL PRODUCT TO SUIT THE STANDARD AND TO FACILITATE THE TRANSFER TO INDUSTRY OF A SAFE FOOD SPECIALTY WITH IMPROVED QUALITY. COLLABORATIVE STUDIES OF OUR RESEARCH GROUP HAVE SHOWN THAT BROWNISH COLORATIONS IN NATURAL GREEN TABLE OLIVES (NON- TREATED WITH ALKALI) ARE DUE TO POLYMERS RESULTING FROM AN ENZYMATIC OXIDATION OF THE O-DIPHENOLIC COMPOUNDS PRESENT IN THE FRESH FRUIT. THEREFORE, A HIGH DEGREE OF INACTIVATION OF THE ENDOGENOUS POLYPHENOLOXIDASE AND PEROXIDASE ENZYMES COULD GREATLY REDUCE THESE UNDESIRED BROWNISH COLORATIONS THAT DIMINISH THE ATTRACTIVENESS OF THE PRODUCT TO THE CONSUMER. FROM THIS HYPOTHESIS, THE GOAL IS TO DEVELOP A COMBINED STRATEGY OF TWO TECHNOLOGICAL FACTORS AIMED AT STABILIZING THE GREEN COLOR OF THE PRODUCT: ENZYME INACTIVATION AND FORMATION OF ZN-CLS BY MEANS OF THERMAL TREATMENTS, ALONE OR IN COMBINATION WITH HIGH PRESSURE. THIS IS A RESEARCH ACTIVITY AIMED AT IMPROVING FOOD QUALITY, IN THIS CASE THE COLOR OF THE TABLE OLIVE SPECIALTY NATURAL GREEN, WITH A DIRECT AND IMPORTANT EFFECT ON THEIR CONSUMPTION PATTERN. "
Project partners: 
AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC)
Project dates: 
January 2016 to December 2018
Contact project
Funding
Funding agency: 
Ministerio de Economía y Competitividad.