真空浓缩对蓝莓花色苷降解的影响

研究真空浓缩处理对蓝莓花色苷残留率的影响,并与热处理结果进行比较,测定不同pH条件下,热处理和真空浓缩处理对蓝莓花色苷残留率的影响。结果表明:蓝莓花色苷在不同pH条件下的热降解均符合一级反应动力学模型(R2>0.9154)。在60℃,pH为1.0、3.0、5.0、7.0、9.0条件下,蓝莓花色苷的降解速率常数分别为0.0114、0.0207、0.0232、0.0924、0.203h-1。pH值越高,花色苷降解速率常数越大,半衰期越短,蓝莓花色苷在酸性条件下稳定性较高。与热处理结果比较显示,真空浓缩过程中蓝莓花色苷稳定性高。     

热处理及贮藏温度对紫甘蓝花色苷稳定性和抗氧化能力的影响

从紫甘蓝中提取纯化花色苷色素,先分别在90、100、120、140℃热处理30 s和2 min,再分别于4、25、45、65℃贮藏21 d,每3天测定花色苷质量浓度及抗氧化能力,探讨热处理及贮藏温度对其稳定性和抗氧化能力的影响规律。结果表明:热处理使花色苷质量浓度下降,花色苷在4℃贮藏稳定性最好,在45℃或更高温度贮藏时,应短于12 d,不同贮藏温度下的花色苷溶液具有还原力及清除羟基自由基、超氧阴离子自由基的能力。因此,含有紫甘蓝花色苷的食品,适宜较低温度热处理及冷藏,减少高温长时间贮藏以避免花色苷损失量过大并伴随颜色改变,但经各温度热处理和贮藏后仍具有抗氧化功能。     

黑加仑果汁中花色苷的贮藏稳定性

以黑加仑果汁为原料,研究不同温度、不同可溶性固形物含量和抗氧化剂（抗坏血酸）存在条件下贮藏过程中果汁花色苷的化学稳定性、降解动力学及颜色变化。结果表明：果汁中花色苷在4 ℃、可溶性固形物含量9°Brix条件下较稳定,随着贮藏温度升高和可溶性固形物含量升高,花色苷残留率越低。贮藏过程中花色苷的降解符合一级反应动力学,反应速率常数k越大,半衰期t1/2越小,活化能Ea越低。添加50 mg/L抗坏血酸使果汁花色苷降解速率常数k明显增大,半衰期t1/2和降解活化能Ea明显减小,因此抗坏血酸对花色苷残留率的减少有促进作用。在贮藏过程中随着时间的推移,花色苷不断的减少,果汁发生褐变,亮度和红色度逐渐降低,黄色度逐渐增加,而且抗坏血酸对贮藏过程中花色苷的颜色变化具有促进作用。     

蓝莓酒渣、果、酒中花色苷成分鉴定及酒渣与果中花色苷抗氧化活性比较

采用XAD-7HP大孔树脂对蓝莓果及蓝莓酒渣花色苷进行纯化,用固相微萃取小柱对蓝莓酒花色苷进行纯化浓缩。通过高效液相色谱-二极管阵列-电喷雾-串联质谱法鉴定了蓝莓果、酒渣、酒中花色苷的组成,并对蓝莓果和蓝莓酒渣花色苷的抗氧化性进行了评价。结果表明：通过XAD-7HP大孔树脂纯化所得的蓝莓果、蓝莓酒渣及利用固相微萃取小柱纯化所得的蓝莓酒中花色苷含量分别为（210.52±5.74）、（151.12±0.88）、（8.93±0.14）mg/g。蓝莓果中鉴定出11 种花色苷;蓝莓酒渣中鉴定出12 种花色苷,其中包括3 种酰化花色苷;蓝莓酒中鉴定出9 种花色苷,其中包含1 种酰化花色苷。蓝莓果和蓝莓酒渣花色苷抗氧化性实验结果表明,蓝莓果和蓝莓酒渣花色苷清除2,2-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐自由基IC50值分别为（1.43±0.02）、（1.19±0.03）μg/mL,清除1,1-二苯基-2-苦基肼自由基IC50值分别为（3.28±0.03）、（2.41±0.01）μg/mL;蓝莓果和蓝莓酒渣花色苷清除自由基能力及还原力均显著优于VC,蓝莓酒渣花色苷抗氧化性显著强于蓝莓果花色苷。     

微波提取对蓝莓花色苷组分及抗氧化活性的影响

研究不同温度下微波提取对蓝莓花色苷组分及抗氧化活性的影响,采用pH示差法测定不同温度下蓝莓总花色苷含量;通过高效液相色谱-串联质谱法(High performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)鉴定蓝莓花色苷组分;采用高效液相色谱法(High-performance liquid chromatography,HPLC)测定蓝莓花色苷单体含量,同时分析蓝莓总花色苷含量、组分以及抗氧化活性的动态变化规律。结果表明:蓝莓花色苷总含量随温度升高呈现先增加后减小的趋势,当温度在50 ℃时,花色苷总含量达到最大值207.39 mg/100 g。经HPLC-MS/MS鉴定蓝莓花色苷共有13种花色苷单体。当温度在30~70 ℃时,蓝莓中所有花色苷单体含量均呈现先增加后减小的趋势;在60 ℃时,仅有芍药-3-葡萄糖苷消失;在70 ℃时,芍药-3-葡萄糖苷和芍药-3-阿拉伯糖苷均消失。蓝莓花色苷的抗氧化活性随温度升高也呈现先增加后减小的趋势,其中对脂质体的抑制率、DPPH和ABTS+自由基清除率均高于Vc,而对.OH自由基的清除能力低于Vc。所建立的动力学模型能有效预测微波提取不同温度下花色苷含量和抗氧化活性的变化规律,研究结果可为蓝莓深加工提供理论依据。     

黑莓、蓝莓复合果酒的加工工艺及贮藏稳定性研究

本研究优化了黑莓、蓝莓复合果酒的加工工艺并对其稳定性进行考察。通过对果酒的酒精度、得率、糖酸比、总多酚、总花色苷含量以及色度、色调、透光率等的比较,考察黑莓、蓝莓的配比,发酵温度,时间和方法对复合果酒品质的影响,以及低温贮藏条件下果酒的稳定性。结果表明,黑莓、蓝莓复合果酒的发酵条件为黑莓、蓝莓的比例在7∶3～1∶1之间,果浆发酵和果汁发酵均可,温度25℃时发酵6～8 d,温度13℃时发酵8～10 d,此工艺发酵得到的黑莓、蓝莓复合果酒总花色苷含量为446～548 mg/L,总多酚含量3240～4500 mg/L,乙醇体积分数8.6%vol～11.0%vol。低温条件下(4～6℃)贮藏70 d,果酒的总花色苷含量下降10%～18%,多酚含量较为稳定。采用果浆或果汁发酵的方法酿造黑莓、蓝莓复合果酒,发酵结束后及时倒罐、低温(4～6℃)贮藏,可以保证产品的品质。     

野生蓝莓酒皮渣花色苷及其抗氧化活性研究

该研究比较了蒸馏前后野生蓝莓酒皮渣中的总酚及花色苷含量、花色苷单体的组成和抗氧化活性。结果表明,蓝莓酒皮渣中总花色苷含量为（8.64±0.13） mg/g,总酚含量为（77.24±1.42） mg/g,抗氧化活性为Trolox当量浓度（3.59±0.11） μmol/g;单体花色苷含量较多的是二甲花翠素-3-O-葡萄糖苷（29.90%）、3′-甲基花翠素-3-O-葡萄糖苷（21.31%）和花翠素-3-O-葡萄糖苷（20.44%）。蒸馏后,皮渣中的总酚及花色苷含量分别下降为（68.11±1.20） mg/g和（5.05±0.09） mg/g,其单体降解率变化在21.64%～43.47%。其中,二甲花翠素-3,5-O-二葡萄糖苷稳定性最差,降解率为43.47%;花青素-3-O-葡萄糖苷较为稳定,降解率为21.64%;Trolox当量浓度下降为（3.07±0.07） μmol/g,皮渣抗氧化能力也降低了14.64%。因此,野生蓝莓果酒发酵产生的皮渣具有较高的利用价值,开发时应尽量避免高温处理。     

壳聚糖涂膜结合冰温贮藏对蓝莓活性成分及抗氧化活性的影响

以蓝莓为试材,研究冷藏、壳聚糖涂膜、冰温和壳聚糖涂膜结合冰温贮藏对蓝莓活性成分含量及抗氧化活性的影响。结果表明,与直接冷藏相比,壳聚糖涂膜、冰温以及壳聚糖涂膜结合冰温贮藏都能有效延缓蓝莓果实贮藏过程中总花色苷、VC、总酚和总黄酮含量的下降,蓝莓果实中总花色苷、总酚和总黄酮含量与1,1-二苯基-2-三硝基苯肼自由基清除能力之间均呈显著正相关,能更好地保持蓝莓的抗氧化活性。而壳聚糖涂膜结合冰温贮藏的效果优于单独采用冰温或壳聚糖涂膜贮藏。因此,壳聚糖涂膜结合冰温贮藏能较好地保持蓝莓活性成分含量及抗氧化活性,是一种较为有效的蓝莓贮藏方法。     

贮藏温度对蓝莓汁单个花色苷降解的影响

为了探讨贮藏温度对蓝莓汁花色苷降解的影响,本文研究了蓝莓汁在4、25、37℃贮藏120期间色泽的变化以及贮藏期间总花色苷和单个花色苷的变化规律,并在此基础上研究了花色苷的降解动力学。结果表明,在4℃下蓝莓汁颜色保存较好,25、37℃变化较大,而贮藏期间总花色苷和单个花色苷呈下降趋势。与零级动力学模型相比,总花色苷和单个花色苷在25、37℃下的降解更符合一级动力学模型,4℃总花色苷的降解与零级和一级动力学模型拟合系数小,单个花色苷中有4种符合一级动力学模型,且温度越高,花色苷的一级降解动力学常数越大,降解速度越快,半衰期越短。含有半乳糖苷的花色苷,其半衰期较阿拉伯糖苷的花色苷略长。总之,蓝莓汁色泽的改变与花色苷的降解密切相关,在较低温度下贮藏,可以明显减少花色苷的损失。     

蓝莓果汁饮料护色工艺

为解决蓝莓饮料在加工贮藏过程中的营养和色泽损失,研究了添加不同质量浓度的护色剂(茶多酚、抗坏血酸和L-赖氨酸)、灭菌条件及光照对蓝莓饮料中花色苷、透光率及色泽的影响。结果表明:蓝莓果汁饮料添加0.1%的抗坏血酸,110℃、15 s下杀菌,贮藏在避光处,可有效延缓花色苷降解、透光率增加和色泽的变化。     

Stability of anthocyanins in frozen and freeze-dried raspberries during long-term storage: in relation to glass transition

Abstract: Anthocyanins, natural plant pigments in the flavonoid group, are responsible for the red color and some of the nutraceutical benefits of raspberries. This study explores anthocyanin degradation in frozen and freeze‐dried raspberries during storage in relation to glass transition temperatures. Frozen raspberries were stored at ?80, ?35, and ?20 °C, while freeze‐dried raspberries were stored at selected water activity (a_w) values ranging from 0.05 to 0.75 at room temperature (23 °C) for more than a year. The characteristic glass transition temperatures (T′_g) of raspberries with high water content and glass transition temperature (T_g) of raspberries with small water content were determined using a differential scanning calorimeter. The pH differential method was used to determine the quantity of anthocyanins in frozen and freeze‐dried raspberries at selected time intervals. The total anthocyanins in raspberries fluctuated during 378 d of storage at ?20 and ?35, and ?80 °C. Anthocyanin degradation in freeze‐dried raspberries ranged from 27% to 32% and 78% to 89% at a_w values of 0.05 to 0.07 and 0.11 to 0.43, respectively, after 1 y. Anthocyanins were not detectable in freeze‐dried raspberries stored at a_w values of 0.53 to 0.75 after 270 d. First order and Weibull equations were used to fit the anthocyanin degradation in freeze‐dried raspberries. The 1^st‐order rate constant (k) of anthocyanin degradation ranged from 0.003 to 0.023 days^?1 at the selected water activities. Significant anthocyanin degradation occurred in both the glassy and rubbery states of freeze‐dried raspberries during long‐term storage. However, the rate of anthocyanin degradation in freeze‐dried raspberries stored in the glassy state was significantly smaller than the rate of anthocyanin degradation in the rubbery state.     

Effect of Four Drying Methods on the Quality of Intermediate Moisture Lowbush Blueberries

Lowbush blueberries have been processed by freeze dry, forced air, vacuum oven, and micro-convection methods to a moisture content of 16-25%. The drying effect on the product quality was evaluated. There were no significant differences in vitamin A and niacin retention except freeze dried berries had higher vitamin C retention. No significant differences occurred in retention of mineral content except higher sodium and lower magnesium were found in the micro-convection and freeze dry methods, respectively. Freeze dried and vacuum dried blueberries had higher soluble solids retention and were darker and redder than forced air or micro-convection dried berries. Freeze dried berries were found to have highest rehydration ratio and lowest bulk density.     

Control of Postharvest Quality in Blueberry Fruit by Combined 1-Methylcyclopropene (1-MCP) and UV-C Irradiation

The objective of this study was to investigate the effects of 1-methylcyclopropene (1-MCP) combined with UV-C irradiation on postharvest quality of blueberry fruit (Vaccinium spp. Berkeley) stored at 4 ± 1 °C for 8 days. Respiration rate, ethylene production, decay incidence, softness, color, total anthocyanin content, malondialdehyde (MDA) content, titratable acid content, soluble solid content, peroxidase (POD), phenylalanine ammonia lyase (PAL), and catalase (CAT) of treated blueberry fruit were examined. The results indicated that treatment with 1-MCP plus UV-C irradiation inhibited respiration rate, ethylene production, decay incidence, and MDA content. The combined treatment also delayed softness, color, titratable acid, and soluble solid content and improved total anthocyanin content of blueberries throughout the storage period at 4 ± 1 °C compared to the untreated samples. The efficiency of the combined treatment (1-MCP + UV-C irradiation) was better than that of 1-MCP or UV-C irradiation alone. Furthermore, combination of 1-MCP and UV-C irradiation effectively enhanced PAL and CAT activities and inhibited the increasing of POD activity in blueberries. Therefore, our results shows that 1-MCP plus UV-C irradiation treatments may be a useful method in maintaining commercial quality and extending shelf life of blueberries.     

高氧处理对草莓果实抗氧化活性的影响

研究了60%和100%O2处理对草莓在5℃15d冷藏及后续20℃空气中1d货架存放期间果实Vc、总酚和花青素含量及抗氧化活性的影响。结果表明,采用60%和100%O2处理能有效抑制草莓果实Vc含量的下降,促进总酚和花青素含量及DPPH自由基清除能力的上升,从而提高了草莓果实的抗氧化活性。统计分析表明,总酚和花青素与DPPH自由基清除能力间具有显著的线性正相关关系,相关系数分别为0.8454和0.8997。因此,高氧处理提高草莓果实的抗氧化活性与果实总酚和花青素含量的增加有关。     

中短波红外干燥对桑葚干燥特性、营养品质及抗氧化活性的影响

为探究中短波红外干燥对桑葚干燥特性、能耗、营养品质及抗氧化活性的影响,将新鲜桑葚在不同干燥温度条件下（50、60、70 ℃）进行中短波红外干制,以相同干燥温度条件下（50、60、70 ℃）的热风干燥为对照,探究不同干燥条件下桑葚的干燥特性、能耗、单体酚类物质、总酚、总黄酮、维生素C、总花色苷的含量及抗氧化活性,并建立桑果中短波红外干燥数学模型。结果表明,中短波红外干燥能够显著（P<0.05）提高桑果的干制效率（50 ℃下干燥效率提高55.7%,60 ℃下干燥效率提高46.1%,70 ℃干燥效率提高33.3%）,Weibull分布模型能够较好地模拟桑果在不同干燥温度下的中短波红外干燥过程,且桑果经中短波红外干燥后能耗较低。干制后桑果共检测出12种酚类物质,其中绿原酸、芦丁、儿茶素为主要的酚类物质。相比传统的热风干燥,中短波红外干燥效率高,且干燥后桑葚的总酚、总黄酮、维生素C、总花色苷含量较高,总酚含量为463.1～568.8 mg/100 g;总黄酮含量为312.6～402.6 mg/100 g;维生素C含量为30.1～37.8 mg/100 g;总花色苷含量为153.6～195.6 mg/100 g。且与热风干燥相比桑果经中短波红外干燥后抗氧化活性显著增强（P<0.05）（DPPH自由基清除能力较热风干燥提高了32.8%～42.6%;铁离子还原能力较热风干燥提高21.1%～34.1%）。中短波红外干燥桑果干燥效率较高,能耗较低,干制品品质较好,故中短波红外干燥是一种优良的桑果干燥方式,可为桑果干制加工提供理论参考。     

Partial Least Squares Analysis of the Relationship Between Chemical Composition and Phenolic Compounds in Blueberry Cultivars

Blueberries (Vaccinium spp.), one of the most widely consumed fruits worldwide, are rich in nutrients and exhibit antioxidant activity. In this study, the partial least squares and principal component analyses were used and the chemical composition and mineral and phenolic compound contents of blueberry cultivars suited to northern China were determined. Blueberries growing in northern China contain a rich variety of biologically active compounds at high concentrations and have high nutritive mineral values. In general, the chemical composition data of the blueberry cultivars examined were similar to those obtained by the US Department of Agriculture (USDA). However, the mineral content data showed iron and potassium concentrations that were slightly higher than those found by the USDA. In addition, the iron concentrations were lower than those found in the literature for Brazilian cultivars. The zinc, magnesium, and vitamin C in blueberries may promote the growth and accumulation of total phenols and anthocyanins, while total acid, iron, and potassium have opposite effects. Total phenols correlated positively with anthocyanins. Differences in protein, total carbohydrate, potassium, and sodium between cultivars could affect total phenol and anthocyanin contents. Adjusting the total acid concentration and reducing the sugar and mineral contents may affect anthocyanin content in blueberries. These changes may improve the nutritional value and fruit quality of blueberries.     

Nisin、溶菌酶用于斑点叉尾鮰鱼片保鲜的研究

以Nisin(乳链菌肽)、溶菌酶及VC(抗坏血酸)为保鲜剂,用于斑点叉尾鮰鱼片的冷藏保鲜,采用正交试验对复合保鲜剂的配比进行优选,并以细菌总数、TVB-N 值、pH 值及感官评分为鲜度指标,测定复合保鲜剂的保鲜效果。结果表明：复合保鲜剂最优配比为0.5% Nisin+0.3% 溶菌酶+3.0% VC,并用乳酸调节pH4.5,用此保鲜剂处理再结合真空包装能使斑点叉尾鮰鱼片在0℃条件下保鲜21d。     

冰箱气调贮藏对水果的保鲜效果

为研究冰箱(5 ℃)气调贮藏对水果保鲜效果的影响,本研究选取了四种水果车厘子、草莓、红元帅苹果、蓝莓,在对照冰箱(常氧21％)和气调冰箱(02含量18～18.5％)中冷藏7 d,通过测定贮藏期间失重率、维生素C含量、花青素含量及果实表层细胞形态来检测气调冰箱的保鲜效果.结果表明:冰箱低温气调贮藏的四种水果保鲜效果最好,...     

壳聚糖/EGCG@MNPs纳米复合包装对低温和常温贮藏蓝莓保鲜效果的影响

本研究以壳聚糖作为薄膜基质,加入负载表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）的黑色素（melanin）纳米颗粒（EGCG@MNPs）,制备了一种活性包装薄膜,用于延长采后蓝莓的贮藏期。首先,壳聚糖/EGCG@MNPs纳米复合膜采用流延法成功制备,装入新鲜蓝莓后形成独立热封包装袋,分别于4和25 ℃条件下贮藏。贮藏期间分析不同时期内蓝莓果实失重率、腐烂率、硬度、呼吸强度、微生物、表观品质等感官指标和理化指标,以探讨该纳米复合包装膜的保鲜效果。结果表明,壳聚糖/EGCG@MNPs纳米复合膜显著延缓了蓝莓果实贮藏期间的失重率、腐烂率和硬度的下降（P<0.05）,有效抑制了蓝莓的呼吸强度,减小了活性物质的消耗和果实表面的褐变程度。贮藏结束时,经过纳米复合包装处理的蓝莓仍保持了较高的花色苷含量,在4和25 ℃环境下保留率分别为90.1%和99.0%;DPPH自由基清除活性分别比对照组高了6.2%和6.3%,使蓝莓果实保持了较好的抗氧化能力,并显著抑制了多酚氧化酶（polyphenol oxidase,PPO）的活性和微生物的生长（P<0.05）,有效改善了蓝莓的感官品质,延缓了蓝莓果实的衰老。综合各项结果得出,壳聚糖/EGCG@MNPs纳米复合包装结合低温的贮藏方法对采后蓝莓的保鲜效果最好。     

Effect of spray drying and storage on the stability of bayberry polyphenols

Bayberry juice was spray dried with maltodextrin (DE 10) as a carrier and then stored under different temperature and water activities (aw). The retention of the total phenolic content (TPC) and total anthocaynins (ACN) during the drying process were about 96% and 94%, respectively, suggesting spray drying was a satisfactory technique for drying heat sensitive polyphenols. Under an aw of 0.11–0.44, the TPC and ACN in bayberry powders decreased by about 6–8% and 7–27%, respectively, after 6 months storage at 4 °C; at 25 °C for the same storage period the decreases were between 6–9% and 9–37%, respectively, while at 40 °C the decreases were in the range 7–37% and 9–94%. The anthocyanin component was more readily degraded relative to other phenolic compounds. The results suggest that bayberry powder should be stored at less than 25 °C and aw of 0.33, on account of greater polyphenol stability under such conditions.