A Systematic Review of Butterfly Pea Flower (Clitoria ternatea L.): Extraction and Application as a Food Freshness pH-Indicator for Polymer-Based Intelligent Packaging

Abstract

The butterfly pea flower (Clitoria ternatea L.) (BPF) has a high anthocyanin content, which can be incorporated into polymer-based films to produce intelligent packaging for real-time food freshness indicators. The objective of this work was to systematically review the polymer characteristics used as BPF extract carriers and their application on various food products as intelligent packaging systems. This systematic review was developed based on scientific reports accessible on the databases provided by PSAS, UPM, and Google Scholar between 2010 and 2023. It covers the morphology, anthocyanin extraction, and applications of anthocyanin-rich colourants from butterfly pea flower (BPF) and as pH indicators in intelligent packaging systems. Probe ultrasonication extraction was successfully employed to extract a higher yield, which showed a 246.48% better extraction of anthocyanins from BPFs for food applications. In comparison to anthocyanins from other natural sources, BPFs have a major benefit in food packaging due to their unique colour spectrum throughout a wide range of pH values. Several studies reported that the immobilisation of BPF in different polymeric film matrixes could affect their physicochemical properties, but they could still effectively monitor the quality of perishable food in real-time. In conclusion, the development of intelligent films employing BPF’s anthocyanins is a potential strategy for the future of food packaging systems.

Optimization of ultrasonic assisted ethanolic extraction for natural pigments from butterfly pea flower applied in Thai dessert using Box-Behnken approach

“…The groups attached to the chromophore affect the molecule's absorption spectrum, shifting it toward longer wavelengths ( Campbell, Pearson, & Marble, 2019 ). These findings align with previous research that indicated the stability of anthocyanin depends on factors such as pH, with low pH levels enhancing stability, as well as the influence of light ( Hasanah et al, 2023 ). This phenomenon, known as Bathochromic or a red shift, refers to the alteration in the absorption or emission wavelengths of a substance, often resulting in a change in color.…”

“…At neutral pH, resonance-stabilized quinonoid anions, representing the purple color of anthocyanins, form through further deprotonation of the quinonoidal species ( Coutinho, Freitas, & Maçanita, 2015 ). The alteration in the color of BPE extracts across various pH levels is attributed to changes in the structure of anthocyanin pigments, which depend on the number of hydroxyl groups within the molecule ( Hasanah, Mohamad Azman, Rozzamri, Zainal Abedin, & Ismail-Fitry, 2023 ). Anthocyanins are classified as phenolic compounds, characterized by a chromophore with a benzene ring.…”

Characteristics of Wet Noodles from Mixed Flour (Wheat and MOCAF) and Butterfly Pea Flower Powder

“…In the combined flour sample, antioxidant activity increased with adding butterfly pea flower powder due to its bioactive content. The anthocyanin content in butterfly pea flowers has been widely used over the years as a potential antioxidant [34]. This is consistent with the increase in total polyphenol value and antioxidant activity.…”

Teaching Acid–Base Fundamentals and Introducing pH Using Butterfly Pea Flower Tea

“…The ternatins found in BPF are more stable, so fading becomes less of an issue. 35 Additionally, BPF is safer than other common educational synthetic indicators such as phenolphthalein, which is a GHS-classified health hazard. For example, the food-safe and indicator properties of BPF have facilitated its use as a freshness monitor of seafood.…”

“…However, this polyphenolic structure is susceptible to oxidation, which can cause the colors to fade. The ternatins found in BPF are more stable, so fading becomes less of an issue . Additionally, BPF is safer than other common educational synthetic indicators such as phenolphthalein, which is a GHS-classified health hazard.…”