American Journal of Food Science and Technology, 2017, Vol. 5, No. 5, 199-203 Available online at http://pubs.sciepub.com/ajfst/5/5/5 ©Science and Education Publishing DOI:10.12691/ajfst-5-5-5 Thermal Degradation of Anthocyanins in Butterfly Pea (Clitoria ternatea L.) Flower Extract at pH 7 Abdullah Muzi Marpaung 1,2 , Nuri Andarwulan 1,3,* , Purwiyatno Hariyadi 1,3 , Didah Nur Faridah 1,3 1 Department of Food Science and Technology, Bogor Agricultural University, Bogor, Indonesia 2 Food Technology Department, Swiss German University Tangerang, Indonesia 3 Southeast Asian Food and Agricultural Science and Technology (SEAFAST) Center, Bogor Agricultural University, Bogor, Indonesia *Corresponding author: andarwulan@yahoo.com Abstract The degradation of anthocyanins from Clitoria ternatea L. flower (CT) extract at pH 7 bottled with 0% and 50% volume of headspace (HS0 and HS50, respectively) were studied at various temperatures (7, 30, 45, 60, 75, 90°C). The extract was stable at 7°C up to 56 days. The effect of the presence of headspace to accelerate the degradation was significance at ≥30°C. The color and chemical degradation were adequately be described by the first order reaction kinetics. However, the degradation at 30°C was faster than at 45°C. The activation energy for the chemical degradation of HS0 and HS50 extracts at 45-90°C were 83.21 and 101.15 kJ/mol. The decrease of A 628 was the fastest, followed by A 580 and A 550 , respectively. By the evidence collected, it was proposed that the degradation of anthocyanins in CT extract was initiated by the unfolding and the deacylation of anionic quinonoidal base species. Keywords: anthocyanins, butterfly pea, degradation, heat, headspace Cite This Article: Abdullah Muzi Marpaung, Nuri Andarwulan, Purwiyatno Hariyadi, and Didah Nur Faridah, “Thermal Degradation of Anthocyanins in Butterfly Pea (Clitoria ternatea L.) Flower Extract at pH 7.” American Journal of Food Science and Technology, vol. 5, no. 5 (2017): 199-203. doi: 10.12691/ajfst-5-5-5. 1. Introduction Polyacylated anthocyanins are anthocyanins containing two or more aromatic acyl groups [1,2]. The aromatic acyl groups configure an intramolecular stacking with the anthocyanidin chromophore that protects the dehydration of flavylium cation to colorless hemiketal [1]. Therefore, the stability of polyacylated anthocyanins at low acidic and neutral conditions is much higher than monoacylated or unacylated anthocyanins, made them as a potential source of natural food colorant [3]. Butterfly pea or Clitoria ternatea L. (CT) is one of the most interesting sources of polyacylated anthocyanins because it provides blue color at a low acidic or neutral solution [4,5,6]. Its stability was reported better than the heavenly blue anthocyanin from morning glory (Ipomoea tricolor) flower [7]. Like other anthocyanins, the stability of polyacylated anthocyanins from CT extract was affected by many factors, especially pH and temperature. Reference [4] reported that the stability of CT extract at pH 4 or below was much higher than at pH 5 or above. The comparable results were also reported by the other researchers [6,8]. At low temperature, the CT extract exhibited a very high stability. The extract at pH ≤ 6.0 remained about 80-90% of its color when kept in the dark at 7°C for 60 days [8]. At temperature 25-90°C, the color stability the extract at pH 3 decreased as temperature increased and fit to the first order kinetic degradation with an activation energy (E a ) 28.66 kJ/mol [4]. The E a value was relatively low, indicating that the degradation rate of anthocyanin of CT extract was less susceptible to temperature increase. Other than pH and temperature, our previous study has shown that the volume of container’s headspace also gave a significant effect to accelerate the color degradation of CT extract at pH 7 [9]. The anthocyanin degradation consists of two different terms, which are color and chemical degradation. The color degradation related to reversible equilibrium change between colored and colorless forms of anthocyanin [10]. The colored species was consisted of the red flavylium cation (AH + ), purple quinonoidal base (A) and blue anionic quinonoidal base (A - ), while the colorless species consisted of hemiketal (B), cis-chalcone (Cc) and trans- chalcone (Ct) [10]. In consequence, the color degradation is preferably studied by determining the decrease of [AH + ] + [A] + [A - ], even though it might be depicted by the decrease of color intensity. Reference [11] determined the color intensity as the absorbance at λ max within the visible region, but for this research, we proposed to determine the color intensity by the total absorbance of the wavelength that represents red, violet, and blue color. The chemical degradation related to the decrease of total anthocyanin due to the irreversible degradation of pigments, mainly arising from cleavage of the chromophore to form benzoic acid and an aldehyde derivative [10]. In general, at below pH 2, the only anthocyanin species exist is the red flavylium cation. Therefore, the total anthocyanin can be represented by the absorbance at λ max of anthocyanin-source extract at pH 1 [12]. The aim of this research was to study the thermal degradation rate of both color and anthocyanin from