Gallic acid as a copigment enhance anthocyanin stabilities and color characteristics in blueberry juice.

The aim of this study was to evaluate the influence of adding copigment gallic acid (GA) on the stability of anthocyanin and color in blueberry juice, and assays were carried out with different anthocyanin:GA molar ratios (1:0, 1:1, 1:3, 1:5) in accelerated experiments (40 °C for 10 days). Results showed that the addition of GA made blueberry juice to appear more crimson color tonality, color saturation and anthocyanins stability. The most obvious hyperchromic effect appeared in juice with 1:5 of anthocyanin:GA molar ratios, and in this ratio, total anthocyanin content (137.67 mg/L) and main anthocyanin peonidin-3-glucoside content (51.68 mg/L) of the blueberry juice were higher than juice without copigment (total anthocyanin of 116.96 mg/L and peonidin-3-glucoside of 34.2 mg/L). Furthermore, anthocyanins in blueberry juice copigmented with molar ratios 1:5 of anthocyanin:GA were more stable at 4 °C than that at 25 °C and 40 °C. Thus, the addition of gallic acid at appropriate levels might be a promising juice process technology to obtain juices with high color quality and anthocyanin stability.

Nanocomplexes composed of chitosan derivatives and ß-Lactoglobulin as a carrier for anthocyanins: Preparation, stability and bioavailability in vitro.

To improve sustained-release property, stability and bioavailability of anthocyanins (ACNs) in vitro, we fabricated the nanocomplexes with chitosan hydrochloride (CHC), carboxymethyl chitosan (CMC) and ß-Lactoglobulin (ß-Lg). Response surface methodology (RSM) combined with desirability function was employed to optimize ACNs-loaded chitosan/ß-Lg (CHC/CMC expressed with chitosan) nanocomplexes with maximum anthocyanins retention rate, preferred particle size and high encapsulation efficiency. The result suggested that the optimized conditions were 5.16 mg/mL of ß-Lg, 1.45 mg/mL of CMC and 6.09 of pH CMC solution. Based on optimized conditions, anthocyanins retention rate, particle size and encapsulation efficiency of ACNs-loaded chitosan/ß-Lg nanocomplexes were 68.9%, 91.71 nm and 69.33%, respectively. ACNs-loaded chitosan/ß-Lg nanocomplexes was more stable in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 6.8) by showing less ACNs release (%) than that ACNs solution and ACNs-loaded CHC/CMC nanocomplexes. Further, stability and bioavailability of ACNs in simulated gastrointestinal (GI) tract were significantly improved by nanocomplexes encapsulation. Compared with ACNs-loaded CHC/CMC nanocomplexes, ACNs-loaded chitosan/ß-Lg nanocomplexes displayed better sustained ACNs release, stability and bioavailability.

Loading of anthocyanins on chitosan nanoparticles influences anthocyanin degradation in gastrointestinal fluids and stability in a beverage.

The optimal preparation parameters to create anthocyanin-loaded chitosan nanoparticles was predicted using response surface methodology (RSM). A Box-Behnken design was used to determine the preparation parameters that would achieve the preferred particle size and high encapsulation efficiency. The result suggested that the optimized conditions were 2.86mg/mL carboxymethyl chitosan (CMC), 0.98mg/mL chitosan hydrochloride (CHC) and 5.97mg anthocyanins. Using the predicted amounts, the experimentally prepared particles averaged 219.53nm with 63.15% encapsulation efficiency. The result was less than 5% different than the predicted result of 214.83nm particle size and 61.80% encapsulation efficiency. Compared with the free anthocyanin solution, the anthocyanin-loaded chitosan nanoparticles showed a slowed degradation in simulated gastrointestinal fluid. Compared with the free anthocyanin solutions in a model beverage system, the stability of the anthocyanins was increased in the anthocyanin-loaded chitosan nanoparticles.

Optimization of Ultrasound-Assisted Extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium ashei) wine pomace.

Ultrasound-Assisted Extraction (UAE) of total anthocyanins (TA) and phenolics (TP) from Blueberry Wine Pomace (BWP) was optimized using Response Surface Methodology (RSM). A Box-Behnken design was used to predict that the optimized conditions were an extraction temperature of 61.03°C, a liquid-solid ratio of 21.70mL/g and a sonication time of 23.67min. Using the modeled optimized conditions, the predicted and experimental yields of TA and TP were within a 2% difference. The yields of TA and TP obtained through the optimized UAE method were higher than those using a Conventional Solvent Extraction (CSE) method. Seven anthocyanins, namely delphinidin-3-O-glucoside, delphindin-3-O-arabinoside, petunidin-3-O-glucoside, cyanidin-3-O-arabinoside, cyanidin-3-O-glucoside, malvidin-3-O-glucoside and malvidin-3-O-arabinoside, were found in the BWP extract from both the UAE and CSE methods.