Today, the physical aspect, including the color as the most impressive and delightful attributes, of food items plays an important role in consumers acceptance determining their commercialization. In this aspect, apart from better organoleptic properties, global consumers also seek healthier, more nutritive and safer components in the food formulations [47]. Typical food colorants, either synthetic or natural, can be used within food formulation according to specific acceptable daily intake. However, it is likely that synthetic colorants have been most widely applied, but their side effects (such as allergic reactions, behavioral and neurocognitive effect) in long term consumption and toxicity have been always a controversy [52]. Therefore, food industries have turned their interest in using natural-based colorants which can satisfy the sensorial and organoleptic aspects, in which most of these natural compounds also act as health promoters [38].

According to their chemical nature and structure, natural-based food colorants are categorized into six classes, such as heme groups, carotenoids, chlorophylls, betalains, flavonoids, and miscellaneous colorants, in which anthocyanins, betacyanin, betaine, carotenoids, polyphenols, curcuminoids are among the most investigated and applied into food items[3,15,59]. Very recently, other natural colorants, such as carminic acid, have been investigated by the research community in the field of food science and technology. Carminic acid (with chemical formula C22H20O13) is a red crimson anthraquinone compound, chemically identified as 1,3,4,6-tetrahydroxy-9,10-anthraquinone substituted by a methyl group at position 8, a carboxy group at position 7 and a 1,5-anhydro-D-glucitol moiety at position 2 via a C-glycosidic linkage (see Fig. 1), displaying a molecular mass of 492,39 g mol−1. Commercially, it is also known as carmine that is a more concentrated solution presenting, at least, 50% of carminic acid. Due to its polyhydroxylated anthraquinone core coupled with a C-glycosyl side chain replete with numerous hydroxyl moieties conducive to hydrogen bonding, carminic acid showcases heightened solubility across an array of media, encompassing aqueous, alcoholic, ester-based, acidic, and alkaline environments, while remaining insusceptible to dissolution in petroleum ether, benzene, and chloroform. In an aqueous solution, it does face susceptibility to photochemical degradation stemming from photon absorption. Nevertheless, this chromophore's remarkable chemical and photostability, characterized by an equilibrium among eight conceivable tautomeric isomers and pronounced redox activity, underscores its utility [17].

Carminic acid is a natural pigment contained in specific insects such as cochineal (Coccus cacti L.), however, there are current advances in the field in which its production can be done via biotechnological approaches [63]. This natural-based pigment has been widely applied in to coffer red shades to various food products, such as alcoholic and non-alcoholic beverages, juices, ice creams, yogurts, jam, meat (sausages) and confectionary products (jellies, snacks), as illustrated in Fig. 1.

Despite its own lack of pronounced taste or aroma, carminic acid indirectly exerts influence over the perception of flavor in select food and beverage products. Its impact on flavor primarily hinges on its remarkable ability to elevate the visual allure of food items [21,65]. The psychological connection between color and flavor establishes and orchestrates an enriched sensory experience for consumers, affecting their perception of taste when encountering food or beverages. Consumers, upon observing a food product adorned with a specific color, tend to associate it with a corresponding taste experience. Herein, the essence of the colorant also becomes relevant, wherein it harmoniously aligns the visual presentation of the product with the anticipated flavor, creating a seamless sensory journey [56]. However, the usage of carminic acid is not just limited to food coloring applications, this natural dye is also applied in textiles, pharmaceuticals, cosmetics, and even drug colorant [4] since it is approved US Food and Drug Administration (FDA). Interestingly, the applications continue being extended due to carmine color is quite stable in a wide range of pH, from 3.5 to 8, presenting exceptional thermal and light stability [7]. Thanks to these advantages, the research community is deeply interested in new research application at this natural-based colorant as evidenced by the growing number of publications over the last decade (see Fig. 2). Surprisingly, it seems that this natural colorant will continue being explored due to its multiple biological activities. Apart from its proved antioxidant activity [6], carminic acid has demonstrated a significant capacity for mitigating inflammation and oxidative stress in the liver. It emerges as a promising therapeutic strategy for addressing non-alcoholic fatty liver disease (NAFLD) induced by metabolic stresses, as reported by [32]. Additionally, the colorant has been conjugated to GnRH peptide hormone and then used as a model for potential photoactive targeted compounds [31].

Towards the purification methods, the research community has proposed different extraction and purification techniques for obtaining carminic acid from insects or via biotechnological pathways. In this sense, there is a current need to reveal the advances for extracting this natural-based colorant. It is worth pointing out that there is not any report reviewing and analyzing the up-to-date research aimed at extracting carminic acid. Therefore, this paper reviews, for the first time, the most advanced research in this field, paying attention to the extraction methods and strategies at purifying carminic acid produced via biotechnological and extracted from insects. Apart from discussing the most relevant results in the field, main emphasis has been focused on the protocols and strategies for the successful extraction and polishing pathways proposed by the research community. By reviewing the ultimate scientific findings, the perspectives are also mentioned.