Kinetic and Thermodynamic Analysis of Anthocyanin Thermal Degradation in Acerola (Malpighia emarginata D.C.) Pulp

Storage Stability and Sensory Properties of Raha Sweet Colored with Crude and Purified Red Grape Anthocyanins and Synthetic Food Colorant

Anthocyanins (ANCs) are water-soluble pigments that are useful as nutraceuticals due to their health benefits. This study was performed to evaluate the storage stability of purified and crude red grape ANCs in Raha Sweet (RS) during storage and to evaluate its sensory properties. ANCs were extracted from red grape pomace and purified with a macroporous resin. RS was prepared and colored with a synthetic food dye, Carmoisine (control), and ANCs (crude and purified). Pigments were extracted from RS weekly for a period of seven weeks and the absorbance was read spectrophotometrically. RS colored with ANCs was evaluated for its color and other sensory properties against another RS colored with the control. Results showed that the degradation of ANCs in RS followed the first-order reaction model, unlike the control, which showed no degradation during storage. The half-life of crude ANCs was three times higher than that of the purified ones, and RS colored with ANCs received a significantly (p < 0.05) lower score for color than that of RS colored with the control. ANCs could provide the food industry with a natural alternative to synthetic dyes to color foods with high sugar content that are stored for a short period of time.

Tropical Red Fruit Blends: The Effect of Combination of Additives on Foaming, Drying and Thermodynamic Properties

Blends combine advantageous characteristics of each species, resulting in products with different flavors and nutritional substances. Moreover, transforming them into powder provides numerous advantages. This work evaluated the properties of three blended foam formulations made from the pulps of tropical red fruits (acerola, guava and pitanga) to determine the foam layer drying kinetics and thermodynamic properties. The foam formulations were prepared by mixing the three pulps in equal proportions (1:1:1), all added with 6% albumin and 1% stabilizing agent. The foams were analyzed for density, volumetric expansion, stability and porosity in six mixing times. Subsequently, they were subjected to drying in an oven with forced air circulation at 4 temperatures, with a layer 0.5 cm thick. Seven mathematical models were fitted to the drying kinetics experimental data to determine the effective diffusivity and thermodynamic properties of the samples. The best mixing times were 5 min for the E2 sample and 30 min for the others. Formulation E2 presented the best results in the foam physical properties, and E3 presented the shortest drying times. All models tested were satisfactorily adjusted, but Page’s model was the most adequate to describe the process. Sample E3 showed the highest diffusivity and sample E2 the lowest activation energy. The drying temperature increase caused reductions in enthalpy and entropy, as well as an increase in Gibbs free energy, indicating an endergonic process. The combination of additives incorporated into the blend influences the drying process: formulation E2 shows greater efficiency in removing water, and formulation E1 presents the highest energy demand.

Bioactive Nutrient Retention during Thermal-Assisted Hydration of Lupins

Lupin, an arid pulse, is gaining popularity as a super food due to its superior nutritional properties. However, it has not been considered for large scale thermal processing, e.g., canning. The present work evaluated the best time/temperature combination to hydrate lupins for canning with minimum losses of bioactive nutrients, pre-biotic fibre, and total solids during hydration. The two lupin species showed a sigmoidal hydration behaviour, which was adequately modelled by the Weibull distribution. The effective diffusivity, D_eff, increased from 7.41 × 10^-11 to 2.08 × 10^-10 m²/s for L. albus and 1.75 × 10^-10 to 1.02 × 10^-9 m²/s for L. angustifolius with increasing temperature, namely, from 25 °C to 85 °C. The lag phase decreased from 145 min to 56 min in L. albus and 61 min to 28 min in L. angustifolius. However, based on the effective hydration rate, reaching the equilibrium moisture, minimum loss of the solids, and prebiotic fibre and phytochemicals, 200 min hydration at 65 °C can be regarded as the optimum temperature of hydration. The findings are thus relevant for designing the hydration protocol to achieve the maximum equilibrium moisture content and yield with the minimum loss of solids (phytochemicals and prebiotic fibres) for L. albus and L. angustifolius.

Cinética da degradação térmica de antocianinas de alaybilí (Vaccinium floribundum Kunth) e macha-macha (Gaultheria glomerata (Cav.) Sleumer)

Resumo As frutas são fontes naturais de antioxidantes, em especial antocianinas; no entanto, de acordo com a literatura, esses compostos têm sensibilidade a certos fatores ambientais, encontrando-se relatos na literatura científica de que a temperatura tem influência na degradação das antocianinas. Nesse sentido, duas frutas nativas da região de Apurímac, Peru, conhecidas como alabilí (Vaccinium floribundum Kunth) e macha-macha (Gaultheria glomerata (Cav.) Sleumer) foram estudadas como fontes de antocianinas e a cinética de degradação foi investigada. Extratos antociânicos com concentrações de 148 e 224 mg L-1 (mg cianidina 3-glucosídeo/L), a partir de frutos de alaybilí e macha-macha, respectivamente, foram obtidos por extração etanólica e, posteriormente, foi avaliada a cinética de degradação nas temperaturas de 30 °C a 60 °C. Constatou-se que os extratos de macha-macha apresentaram maior degradação em relação aos extratos de alaybilí. Foi confirmado que a cinética de primeira ordem representa melhor a degradação das antocianinas, com constantes de velocidade variando de 7,07·10-4 a 5,96·10-3 h-1 para alaybilí e de 1,62·10-3 a 1,71·10-2 h-1 para macha-macha, com energias de ativação de 60,2 e 70,4 kJ mol-1, respectivamente. Ambos os frutos são fontes de antocianinas, sendo que as antocianinas presentes no fruto de alaybilí apresentam maior estabilidade à temperatura.

A Review of the Current Knowledge of Thermal Stability of Anthocyanins and Approaches to Their Stabilization to Heat

Anthocyanins are colored valuable biocompounds, of which extraction increases globally, although functional applications are restrained by their limited environmental stability. Temperature is a critical parameter of food industrial processing that impacts on the food matrix, particularly affecting heat-sensitive compounds such as anthocyanins. Due to the notable scientific progress in the field of thermal stability of anthocyanins, an analytical and synthetic integration of published data is required. This review focuses on the molecular mechanisms and the kinetic parameters of anthocyanin degradation during heating, both in extracts and real food matrices. Several kinetic models (Arrhenius, Eyring, Ball) of anthocyanin degradation were studied. Crude extracts deliver more thermally stable anthocyanins than purified ones. A different anthocyanin behavior pattern within real food products subjected to thermal processing has been observed due to interactions with some nutrients (proteins, polysaccharides). The most recent studies on the stabilization of anthocyanins by linkages to other molecules using classical and innovative methods are summarized. Ensuring appropriate thermal conditions for processing anthocyanin-rich food will allow a rational design for the future development of stable functional products, which retain these bioactive molecules and their functionalities to a great extent.

A review of the interaction between anthocyanins and proteins

Anthocyanins have good physiological functions, but they are unstable. The interaction between anthocyanins and proteins can improve the stability, nutritional and functional properties of the complex. This paper reviews the structural changes of complex of anthocyanins interacting with proteins from different sources. By circular dichroism (CD) spectroscopy, it was found that the contents of α-helix (from 15.90%-42.40% to 17.60%-52.80%) or β-sheet (from 29.00%-50.00% to 29.40%-57.00%) of the anthocyanins-proteins complex increased. Fourier transform infrared spectroscopy showed that the regions of amide I (from 1627.87-1641.41 cm^-1 to 1643.34-1651.02 cm^-1) and amide II (from 1537.00-1540.25 cm^-1 to 1539.00-1543.75 cm^-1) of anthocyanins-proteins complex were shifted. Fluorescence spectroscopy showed that the fluorescence intensity of the complex decreased from 150-5100 to 40-3900 a.u. The thermodynamic analysis showed that there were hydrophobic interactions, electrostatic and hydrogen bonding interactions between anthocyanins and proteins. The kinetic analysis showed that the half-life and activation energy of the complex increased. The stability, antioxidant, digestion, absorption, and emulsification of the complex were improved. This provides a reference for the study and application of anthocyanins and proteins interactions.

Analysis of the Anthocyanin Degradation in Blue Honeysuckle Berry under Microwave Assisted Foam-Mat Drying

Changes in nutrient content and bioactivity are important indicators to evaluate the quality of products. Berries are rich in antioxidant anthocyanins, which are prone to degradation during drying. The effects of different variables on the stability of anthocyanins in berry puree during microwave assisted foam-mat drying (MFD) was investigated by path analysis and degradation kinetics analysis. The experimental results showed that the degradation of anthocyanins mainly occurred in the last drying stage. The temperature and the moisture content have both direct and indirect effects on the anthocyanin stability. The direct path coefficient of the moisture content on anthocyanins was 0.985, and the direct path coefficient of temperature on anthocyanins was −0.933. The moisture content to temperature ratio (M/T) was first put forward to estimate the anthocyanin degradation. The results of the regression analysis confirmed that the anthocyanins were stable at M/T of 0.96–3.60. A finite element simulation model was established to predict the anthocyanin degradation rate and content. These research results could provide a theoretical reference for use in optimizing the MFD processing technologies.

Tropical fruit juice: effect of thermal treatment and storage time on sensory and functional properties

Tropical fruits rich in polyphenols, ascorbic acid, and high antioxidant capacity can enhance the functional composition, flavor as well as the overall acceptance of their juices. The aim of this study was to evaluate the effects of pasteurization and storage time on the physical, chemical, and sensory quality parameters of two formulations of tropical fruit juice blends with high antioxidant capacity. Two formulations with different concentrations of acai, camu-camu, acerola, cashew apple, yellow mombin, and pineapple were pasteurized at 85 °C for 30 s, hot-filled in glass bottles, and stored in refrigerated conditions (5 °C). Analyses for color, total antioxidant activity, total polyphenols, carotenoids, ascorbic acid, and sensory quality were performed before and after pasteurization as well as at 90 and 180 day of storage. Pasteurization did not negatively affect the concentration of functional components and sensory properties. However, the storage time negatively influenced the sensory quality and reduced the ascorbic acid content of both the formulations. Further, the acceptability and the nutritional quality were still high in these products after 180-days of storage, thus, not preventing their consumption.