Olea europaea PLS regression model PLS-DA Research & information: general accelerated shelf-life tests acidic hydrolysis alginate/pectin beads anaerobic codigestion antioxidant activity antioxidants artificial neural networks authentication authenticity autochthonous cultivars biocompounds biodiversity biomethane biscuits botanical origin breadsticks brown-amber glass by-products carbon NMR chemometrics chlorophyll choice experiment (CE) circular economy clones color consumer attitude