Cold storage of apples (cv. Granny Smith) and changes in phenolic compounds

 The Granny Smith variety of apple behaves differently to other apple cultivars, in that it needs an abnormally long time to ripen at room temperature. Its maturation has been accelerated by low-temperature stress. Fruit collected at commercial maturity were chosen and submitted to storage at 4 °C for 10 days and rewarming at 22 °C, to assay the influence of cold storage on their content of phenolic compounds. The behaviour of phenolic compounds was different in peel and in pulp. In the pulp, apple phenolic compounds decreased during the development period and during the cold treatment. In the peel, the quantity of phenolic compounds increased with time after the cold treatment, reversing their normal behaviour during the development period. Received: 11 March 1996     

澳洲青苹加工适性的测定研究

澳洲青苹是高酸品种之一，文中对澳洲青苹的主要加工特性进行了研究，并与其他苹果加工品种的同类指标作了比较。结果表明，澳洲青苹的硬度为8.106kg／cm~2，出汁率75.702％，固形物含量13.62％，有机酸含量0.655％，Vc含量87.2mg／kg，而引起果汁酶促褐变的主要底物——多酚类物质(以绿原酸为主)为61.82mg／L。与常用加工品种相比，其各项指标更符合果汁加工的要求。     

澳洲青苹果实不同部位香气成分差异分析

采用顶空固相微萃取结合气质联用检测澳洲青苹果皮、果肉、果心的香气成分;共检测到80 种果实香气成分,主要为醛类、醇类、酯类和烯烃类。果皮、果肉和果心,香味组分及其含量差异较大。果皮是香气成分最集中的部位,共分离出55 种,其中C6 醛类3 种,相对含量39.515%,比例最高;酯类23 种最丰富,相对含量14.240%,乙酸己酯、环丁醇、(E)-1,4- 己二烯、(3E,5E)-1,3,5- 庚三烯、3,6- 二甲基-3,6- 二乙基-1,4- 环己二烯为芳香物质中相对含量较高的特有成分。果肉检测出香气成分18 种,其中醇类4 种,相对含量31.391%,比例最高,2- 甲基-1- 丁醇占其醇类约94.814%,丙酸丙酯、甲酸己酯相对含量较高且为果肉特征芳香物质。果心检测出香气成分30 种,C6 醛类两种,相对含量47.398%,比例最高;醇类4 种,相对含量42.455%,2- 甲基-1-丁醇和1- 己醇占其醇类96.639%;果皮香气成分种类最丰富,提供酯类背景香气。苹果各部位主要香气物质中,丙酸丙酯、甲酸己酯由果肉产生,2- 甲基-1- 丁醇主要由果心和果肉产生,1- 己醇由果心和果皮产生,α - 法呢烯主要存在于果皮和果肉中,(E)-2- 己烯醛和正己醛在果皮、果肉、果心中含量均较高,为澳洲青苹果实特征性香气,澳洲青苹果实香气由各部位香气成分相互作用产生。     

Monomeric phenolics in different parts of high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf): a promising source of antioxidants for application in nutraceuticals

The high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf) possessing deep red peel and light red flesh is widely distributed in China. To determine if a useful apple variety is being ignored, the monomeric phenolic profiles and antioxidant activities of peel, flesh, pomace, whole fruit and juice were evaluated. The results were compared to those of ‘Fuji’ and ‘Granny Smith’ apples. The high‐acid apple possessing the highest total phenolic and anthocyanin contents among three apple varieties contained the most chlorogenic acid, phloridzin, epicatechin, ferulic acid, catechin, vanillic acid, p‐coumaric acid and caffeic acid. The extraction yields of phenolics (64%) and anthocyanins (89%) from the high‐acid apple to juice were the highest. The high‐acid apple possessing the greatest antioxidant activity had the strongest antihaemolysis activity, indicating that it could be used to produce juice and value‐added ingredient to assist in the prevention of chronic disease.     

Chemical profile, functional and antioxidant properties of tomato peel fiber

Tomato processing residue is defined as a secondary raw material that can increase its value, being considered a potential source of dietary fiber and bioactive compounds. Commercial tomato peel fiber has been analyzed to ascertain the proximate and nutritional composition (moisture, fat, protein, dietary fiber, ash, and minerals), the fractions (insoluble, IDF, and soluble, and SDF) and sugar composition of dietary fiber, functional properties (water retention capacity, WRC, swelling capacity, SWC, fat absorption capacity, FAC, glucose diffusion retardation index, GDRI, and osmotic pressure), total antioxidant activity (AA), and the content of antioxidant bioactive compounds (phenolic compounds and lycopene). To extract phenolic compounds and dietary fiber, three methods were assayed in this study: enzyme hydrolysis, maceration, and ultrasonic assistance. The content of TDF was 84.16%, and the major fraction was the IDF (71.82%), formed mainly by hemicelluloses. Tomato peel fiber retained 6.76 g of water/g as WRC, and it was significantly correlated with the IDF content. In addition, the content of IDF determined the low FAC and SWC and the GDRI at 60 min (39.22%). The main phenolic compound was rutin, followed by naringenin, rutin derivatives, and chlorogenic acid derivatives. These were better extracted using ultrasonic assistance, whereas lycopene showed mean values between 3 and 4 mg/100 g. The AA of tomato peel fiber was low, since the phenolic compounds are mainly bound to the cell wall of plant, showing a low capacity for scavenging radicals. Due to its chemical profile and functional properties, tomato peel fiber can be used as a food supplement, improving the different physical, chemical, and nutritional properties of foods. However the color and flavor of this product must be considered in its applications to avoid a negative effect on the sensory characteristic of the foods to which it is added.     

加工苹果——澳洲青苹品质的测定研究

文中对澳洲青苹的主要加工特性进行了研究,并与其他苹果加工品种的同类指标作了比较。结果表明,澳洲青苹的硬度为8．106kg／cm^2,出汁率75．702％,固形物含量13．62％,有机酸含量0．655％,Vc含量87．2mg／kg,而引起果汁酶促褐变的主要底物一多酚类物质（以绿原酸为主）为61．82mg／L。与常用加工品种相比,澳洲青苹是目前最适合加工浓缩果汁的品种之一。     

Fruit‐based functional foods I: production of food‐grade apple fibre ingredients

With the increased consumer interest in fibre‐enriched functional foods, industrial‐scale methods for functional fibre production are demanded. The development of a food‐grade fibre preparation method at lab scale that is feasible for industrial scale‐up is a pre‐requisite. This paper describes two lab‐scale fibre preparation methods that have potential to be scaled up to industrial setting for the production of fruit fibres containing desired bioactives and functionality. The two methods, one aqueous and the other ethanolic, were used to isolate fibres from Granny Smith apples (Malus domestica Borkh cv. ‘Granny Smith’). In the aqueous method, ground apple tissues were suspended in HEPES buffer (20 mM, pH 6.5), and then mechanically ruptured using an Ultra‐Turrax and ring grinder. Between steps, the cell‐wall materials were washed with the HEPES buffer. In the ethanolic method, ground apple tissues were stirred in 72% ethanol at 4 °C, filtered, re‐suspended in 72% ethanol and then washed. Microscopic examination and chemical analysis were performed on the resultant fibres. The aqueous method produced natural and uniform dietary fibres in the form of plant cell walls containing 0.282 g uronic acid per g dried fibre. By comparisons, the ethanolic method produced crude fibres containing only 0.182 g uronic acid per g dried fibre, the lower uronic acid content indicating the presence of impurities. Thus, the aqueous method appeared to be advantageous in terms of the retained pectic polysaccharide content and cost‐effectness for industrial scale‐up. Further characterisation using Folin‐Ciocalteu assay and high performance liquid chromatography indicates that the fibres obtained by the aqueous method contained significant amounts of phenolic compounds (2.6 mg catechin equivalent per g dried fibre). These results suggest that fibres obtained by the aqueous method may be more suitable for functional food applications where fibres with high pectic polysaccharide and beneficial phenolic antioxidants are preferred.     

Comparison of antioxidant capacity and phenolic composition of peel and flesh of some apple varieties

BACKGROUND: Apples contain a large concentration of phenolic compounds, dependent on factors such as cultivar, harvest, storage conditions, and processing. This study aims to identify the essential phenolic compounds present in various apple varieties, to measure their total antioxidant capacity (TAC) with the CUPRAC (cupric ion reducing antioxidant capacity) and ABTS (2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonate)) methods, and to correlate their TAC values with HPLC findings. RESULTS: The order of TAC (mmol Trolox g^?1 fresh weight) of apple peels determined with the CUPRAC method was: Granny Smith > Amasya > Sky Spur > Ervin Spur > King Luscious ≥ Arap Kizi ≥ Lutz Golden. The theoretically calculated TAC values of HPLC‐quantified compounds, with the aid of the combined HPLC‐CUPRAC method, accounted for 18.4–33.5% of the experimentally observed CUPRAC capacity of peel extracts and 19.5–56.3% of flesh extracts, depending on apple variety. CONCLUSION: In synthetic samples of apple antioxidants, the CUPRAC‐TAC values of constituents, identified and analyzed by HPLC, proved to be additive, enabling measurement of the cooperative action of antioxidants using the proposed methodology. Apple peel showed higher contents of phenolics and therefore higher TAC than apple flesh, confirming the health benefit of the consumption of apples together with peel. © 2012 Society of Chemical Industry     

澳洲青苹加工品质的测定

测定了高酸品种澳洲青苹的固形物、有机酸和引起果汁褐变的主要成份——多酚类物质(以绿原酸计)，固形物含量比其他品种苹果的平均含量高1．51个百分点，有机酸含量高于其它苹果0．122个百分点，而绿原酸仅为61．82mg／L，远远低于普通苹果(秦冠)的绿原酸含量258．57mg／L。实验表明，澳洲青苹是目前最适合加工浓缩果汁的品种之一。     

Effect of vacuum impregnation on the phenolic content of Granny Smith and Stark Delicious frozen apple <Emphasis Type="Italic">cvv</Emphasis>

ABTS•+ test, o-diphenols (spectrophotometric) and HPLC-DAD phenolic content in vacuum impregnated apple slices from Stark Delicious and Granny Smith cvv. were studied. Vacuum impregnation (VI) was carried out in a pilot plant using an aqueous solution containing 37.9% dextrose, 15.2% sucrose, 1.0% ascorbic acid, 0.25% calcium chloride and 0.25% sodium chloride. The impregnation time was 30 min and the vacuum pressure was 100 mbar; the temperature was 25 °C during all processing steps and the solution/fruit ratio was 11:1. At the end of VI, samples were left 5 min in syrup. They were then rinsed with water, drained in a vibrating screen and quickly frozen. A significant decrease (p < 0.05) of the o-diphenol content was seen (17.84 and 12.32% of the initial content in Stark and Granny varieties, respectively). The same trend was confirmed by HPLC-DAD where reductions in total phenols were 21.57 and 26.86% in Stark and Granny, respectively. Individual phenolic compounds showed different rates of depletion, although in some cases there was no reduction. The ABTS•+ test was strongly affected by the presence of ascorbic acid (AA), which was much higher in treated samples. Sensory evaluation showed higher values of hardness, crispness, juiciness and sourness in VI Granny Smith than VI Stark delicious, with a higher retention of texture parameters in the former. Finally, sweetness was slightly higher in VI Stark. An erratum to this article can be found at     

Effect of Cell Wall Properties on Porosity and Shrinkage of Dried Apple

Water removal during drying depends on the pathway of water migration from food materials. Moreover, the water removal rate also depends on the characteristics of the cell wall of plant tissue. In this study, the influence of cell wall properties on porosity and shrinkage of dried product was investigated. Cell wall stiffness depends on a complex combination of plant cell microstructure, composition of food materials and the water-holding capacity of the cell. In this work, a preliminary investigation of the cell wall properties of apple was conducted in order to predict changes of porosity and shrinkage during drying. Cell wall characteristics of two types of apple (Granny Smith and Red Delicious) were investigated under convective drying to correlate with porosity and shrinkage. A scanning electron microscope (SEM), 2kN Intron, pycnometer and ImageJ software were used in order to measure and analyse cell characteristics, water holding capacity of cell walls, porosity and shrinkage. The cell firmness of the Red Delicious apple was found to be higher than for Granny Smith apples. A remarkable relationship was observed between cell wall characteristics when compare with heat and mass transfer characteristics. It was also found that the evolution of porosity and shrinkage are noticeably influenced by the nature of the cell wall during convective drying. This study has revealed a better understanding of porosity and the shrinkage of dried food at microscopy (cell) level, and will provide better insights to attain energy-effective drying processes and improved quality of dried foods.     

Control of <Emphasis Type="Italic">Penicillium expansum</Emphasis> and patulin accumulation on apples by quercetin and umbelliferone

The effectiveness of seven phenolic compounds (esculetin, ferulic acid, quercetin, resveratrol, scopoletin, scoparone and umbelliferone) in controlling Penicillium expansum growth and patulin accumulation was evaluated by both in vitro and in vivo studies. The in vitro screening showed that quercetin and umbelliferone were the most effective compounds in controlling Penicillium growth and patulin accumulation, respectively. Quercetin and umbelliferone, resulted to be effective also in the in vivo screening, were further tested (alone and in combination) on Granny Smith and Golden Delicious apples. The efficacy in controlling Penicillium growth was better expressed on Golden Delicious than on Granny Smith apples, with quercetin providing a better control of both incidence of decay and disease severity as compared to umbelliferone. Both compounds exerted a considerable control of patulin accumulation on the two apple cultivars. Quercetin and umbelliferone can be considered as natural compounds to be used as alternative strategy to chemical fungicides in postharvest control of P. expansum infections on apples.     

Effect of frozen storage on the phenolic content of vacuum impregnated Granny Smith and Stark Delicious apple <Emphasis Type="Italic">cvv</Emphasis>.

The phenolic fraction modification was evaluated in untreated vacuum impregnated frozen apple slices from two varieties (Granny Smith and Stark Delicious) a few days after freezing and after 12 months of frozen storage. After 12 months the phenolic content of both fresh and vacuum impregnated apple slices varied greatly. The most important change was the increase of many polymeric flavan-3-ols, which may be due to hydrolysis of polymeric procyanidins. Furthermore, there was significant correlation (r ² = 0.52, P < 0.05) between the increase in flavan-3-ols and the decrease in pH. In fact, control Stark slices presented the highest pH, and had no statistically significant increase in flavan-3-ols. Other classes of phenolic compounds were decreased in apple slices following frozen storage.     

Phenolic compounds in some apple (Malus domestica Borkh) cultivars of organic and integrated production

Eleven organically grown apple cultivars and 11 apple cultivars of integrated production from Austria and Slovenia were analyzed by HPLC for the content of phenolic compounds in peel and pulp. We identified chlorogenic acid, p‐coumaric acid, procyanidin B3, protocatechuic acid, (?)‐epicatechin, phloridzin, rutin and quercetin‐3‐rhamnoside in apple peel. In apple pulp, (+)‐catechin was also identified in all the cultivars. Some other phenols (procyanidin B3, rutin and quercetin‐3‐rhamnoside) could not be identified or were not properly separated. With regard to the phenolic content in the apple peel, there were no differences between organically grown apple cultivars and apple cultivars of integrated production. Organically grown apples, however, exhibited a higher content of phenolic substances in the apple pulp compared with the apple cultivars of integrated production. This may be due either to the different genotype source or to the growing technology. Higher concentrations of phenolic compounds in organically grown cultivars could be a result of plant response to stress. The apple peel contained higher concentrations of identified phenols than the pulp. The apple peel represents up to 10% of the whole fruit; therefore the phenolsic compounds in the pulp are of greater importance to the consumer than the phenolic compounds in the peel. Copyright © 2005 Society of Chemical Industry     

不同品种苹果果实主要酚类物质含量的研究

用高效液相色谱仪测定了不同品种苹果果实绿原酸、儿茶素、表儿茶素、根皮素和槲皮素等主要酚类物质的含量。结果表明,不同品种苹果果肉酚类物质总量以富士和新红星最高,金冠最低。富士苹果果肉酚类物质以绿原酸为主,新红星和王林苹果果肉以表儿茶素为主。不同品种苹果果皮酚类物质总量以新红星最高,各品种苹果果皮酚类物质总量均高于果肉。果皮中酚类物质以黄烷-3-醇类为主。     

响应面试验优化复合酶法提取青蛇果多酚工艺及其抗氧化活性

以高酸度苹果、富含原花青素的青蛇果为原料,采用单因素试验和Box-Behnken试验设计优化了复合酶辅助提取青蛇果多酚的工艺参数。结果表明：最适多酚提取的复合酶为纤维素酶和果胶酶（质量比2∶1）、酶解温度62.5 ℃、提取时间82.9 min、pH 3.7,多酚得率最高可达5.07%。统计学分析显示,所选响应面模型合适,并能广泛用于青蛇果多酚的分析和预测。同时,酶法辅助提取青蛇果多酚的粗提物还具有较好的Fe3＋还原能力和1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力,其对DPPH自由基的半数抑制浓度（IC50值）为22.72 μg/mL,可以作为一种良好的食品添加剂和抗氧化剂深度开发利用。     

The effect of calcium and cellular permeabilization on the structure of the parenchyma of osmotic dehydrated ‘Granny Smith’ apple

Calcium plays a very important role in the maintenance of quality in vegetable foods and it is used as a texturing agent to preserve the structure of minimally processed vegetables. The osmotic dehydration (OD) of ‘Granny Smith’ apple parenchyma by immersion in a sucrose solution allows us to obtain products with sensorial characteristics similar to those of fresh products, but it produces a loss of cellular integrity. Here we study the use of calcium as a possible preservative for the microstructural integrity of the product during OD, as well as to test whether cellular permeabilization improves the impact of calcium on the edible parenchyma of the ‘Granny Smith’ apple. Sodium dodecyl sulfate (SDS) has been used for convenience as a permeating agent although we recognize this may not be used in practice. The microstructure of the OD apple treated with calcium chloride and with SDS has been compared with fresh apple by means of light microscopy, transmission electron microscopy and low temperature scanning electron microscopy. The results show that calcium has a protective effect on the structural integrity during OD: it strengthens the cellular walls cements, avoids cellular collapse and protects protoplasts from plasmolysis. Although SDS favours calcium penetration, its use is not advisable since it encourages the destructuring effect of the OD and counteracts the consolidating effect of calcium. Copyright © 2004 Society of Chemical Industry     

苹果籽油超临界萃取及其特性研究

以富士、新红星及澳洲青苹三个品种苹果籽为原料,确定物理特性参数后用超临界二氧化碳萃取技术提取油脂,测定所得油脂理化指标,并分析油脂脂肪酸组成。结果表明:三个品种苹果籽均富含粗蛋白和粗脂肪;在SFE–CO2较优提取条件下,富士、新红星和澳洲青苹苹果籽油得率分别为21.78%、20.64%和20.82%;所得油脂理化指标均符合食用油标准;苹果籽油富含不饱和脂肪酸,尤其是亚油酸,在富士、新红星和澳洲青苹苹果籽油中含量分别为51.25%、50.14%和50.70%;因而,苹果籽油具有良好商业开发前景。     

柑橘皮渣膳食纤维的特性及其在食品中的应用

膳食纤维是人类的“第七种营养素”,具有预防肥胖,调节肠道菌群等生理活性。柑橘皮渣是膳食纤维的良好来源之一,目前国内对于柑橘皮渣膳食纤维的研究主要集中在制备工艺,但对柑橘皮渣膳食纤维在食品中的工业化应用研究还比较薄弱。因此,开发和利用柑橘皮渣膳食纤维已成为当前研究的热点。由于柑橘皮渣膳食纤维具有优异的理化性质,能够作为一种膳食补充剂应用于食品生产。因此本文主要对柑橘皮渣中膳食纤维的种类、含量、膳食纤维的性质及柑橘皮渣膳食纤维在食品中的应用进行了概述,以期为更好地开发和利用柑橘皮渣中的膳食纤维提供参考。     

Near infrared spectroscopy to predict bitter pit development in different varieties of apples

Bitter pit is a physiological disorder in apples. Several major apple varieties are susceptible to this disorder that poses a great challenge to growers and the associated industry as it significantly reduces the produce utilization value and marketability. The current method of bitter pit detection is through visual assessment of symptoms. Near infrared (NIR) spectroscopy is a non-invasive technique that can be utilized towards detecting bitter pit development in fruits in pre-/non-symptomatic stages. Therefore, NIR spectra (935–2500 nm) of apples were collected from healthy and bitter pit Honeycrisp, Golden Delicious, and Granny Smith apples from a commercial orchard. The apples were stored in a controlled environment and spectral reflectance data were acquired at days 0, 7, 14, 35, and 63 after harvest. Chemical analysis was performed at the end of the storage period to estimate calcium, magnesium, and potassium content in the fruit peel. Partial least square regression (PLSR) was used to identify the apples as healthy or bitter pit using NIR-based spectral features. In addition, specific spectral features were selected by implementing two feature extraction methods: PLSR and stepwise discriminant analysis (SDA) on day 63 spectral dataset. The PLSR and SDA-based selected features from day 63 in Honeycrisp apples classified the same dataset with classification accuracies of about 100% with both methods. Regression analysis indicated a strong relationship between the PLSR-based spectral features and magnesium-to-calcium ratio in fruit peel in all three (Honeycrisp, Golden Delicious, and Granny Smith) apple varieties.