Freshness and spoilage indicators of spinach for waste valorization: a review

Spinach (Spinacia oleracea L.) can be produced all around the world. It has been a part of natural therapy since ancient times. Despite its significant economic and nutritional value, these attributes do not change the fact that spinach is highly perishable. Adding to this challenge is the absence of a precise definition, standard, or criteria for determining when spinach reaches an inedible state due to spoilage. Furthermore, there is a lack of guidelines regarding the potential uses of spinach after it has spoiled, particularly in terms of waste management. This review aims to clarify the point at which spinach is classified as waste and offers insights into strategies for valorizing spinach waste.