Osmotic dehydration pretreatment for improving the quality attributes of frozen mango: effects of different osmotic solutes and concentrations on the samples

The effect of osmotic dehydration pretreatment on the quality attributes (e.g. colour, hardness, drip loss, vitamin C content and pH) of frozen mango cuboids in different osmotic solutions (sucrose, glucose and maltose) and concentrations (30, 45 and 60% (wt/wt)) was investigated. Results revealed that melting temperature of mango cuboids was affected by both solute type and solid mass fraction. In addition, the dehydrofrozen samples pretreated in maltose had higher quality in vitamin C content (increasing by 23.5–73.0%), colour (colour change reducing by 2.6–39.2%) and drip loss (reducing by 0.7–9.7%) than those pretreated in other osmotic solutions. The cuboids pretreated in glucose displayed higher hardness (increasing by 16.4–36.2%). Based on principal component analysis and group distance, osmotic dehydration in 45% maltose was proposed as the most favourable freezing conditions with the highest sensory score (6.8). The current work indicates osmotic dehydration significantly improves frozen mango quality.     

Optimisation of osmotic dehydration of 'Tommy Atkins' mango fruit

Osmotic dehydration of mango in sucrose solution as influenced by temperature (30–50 °C), immersion time (60–150 min) and solution concentration (40–60% w/w) was studied through response surface methodology. Responses of water loss and solid gain were fitted to polynomials, with multiple correlation coefficients ranging from 0.72 to 0.95, respectively. The fitted functions were optimised for maximum water loss and minimised incorporation of solids in order to obtain a product resembling non-processed fruit. Optimum conditions to obtain water removal >25% with solid uptake lower than 6% could be obtained using a 44% (w/w) sucrose solution concentration, temperatures up to 38 °C and immersion times up to 80 min.     

Texture improvement of fresh and frozen mangoes with pectin methylesterase and calcium infusion

BACKGROUND: A major problem of mango products is texture loss. The effect of commercial pectin methylesterase (PME) and calcium infusion on improvement of the texture of both fresh and frozen‐thawed mango cubes was investigated in the present study. RESULTS: The weight gain and moisture content of mango samples were greater at relatively high vacuum level (10 kPa). The PME activity of samples infused with PME and calcium at 10 kPa increased fourfold in comparison with that of control and water‐infused samples. The combined effect of PME and calcium was found to improve the texture and microstructure of both fresh and frozen‐thawed mangoes. Fresh mangoes infused with PME and calcium at 10 kPa showed significantly higher firmness than control fresh samples. Frozen‐thawed mangoes infused with PME and calcium at 50 kPa and atmospheric pressure had superior texture and microstructure in comparison with control frozen‐thawed samples. CONCLUSION: The results of the present analysis allow for a better appreciation of the role of PME, calcium and appropriate infusion conditions in improving the texture of both fresh and frozen‐thawed mangoes. Copyright © 2012 Society of Chemical Industry     

Effects of variety, ripening condition and ripening stage on the quality of sulphite-free dried mango slices

The influence of cultivar and fruit ripeness on sensory properties and all-trans-β-carotene contents of dried mango slices was evaluated. Different ripeness stages, quantitatively defined by a ripening index (RPI), were generated from a single lot per cultivar by subjecting mature-green mangoes of the cultivars ‘Nam Dokmai’, ‘Kaew’, and ‘Chok Anan’ to different postharvest ripening regimes. Fruits were ripened for 2 and 3 days at 24±2 °C/45–60% relative humidity (RH) and 33±2 °C/50–70% RH, with application of calcium carbide (CaC₂) or 2-chloroethylphosphonic acid (CEPA, Ride^®) beside the control, terminating postharvest ripening when fruit firmness allowed proper peeling and slicing. After ripening, fruits were washed, peeled, sliced and subsequently dried in a conventional tray dryer at 70 °C for 8–10 h, until the water activity of the dried fruits was below 0.65. Mangoes cv. ‘Kaew’, followed by ‘Chok Anan’, were more suitable for drying than cv. ‘Nam Dokmai’ because of superior all-trans-β-carotene contents of the products. Maximum β-carotene contents of dried mango slices from cvs. ‘Chok Anan’ and ‘Kaew’ corresponded to retinol equivalents of 333–383 and 483–905 per 100 g of edible portion (dry weight), meeting daily mean requirements of vitamin A for adults according to FAO/WHO. Similar to the fresh fruit, exponential rise of all-trans-β-carotene contents with increasing fruit ripeness was also observed for the dried products of cvs. ‘Nam Dokmai’ and ‘Chok Anan’. Consistently, accelerated ripening at 33 °C, instead of 24 °C, resulted in higher all-trans-β-carotene contents of dried fruits. Both good sensory acceptance and cultivar-specific maximum all-trans-β-carotene contents of 13–16 and 20–23 mg kg^?1 usually characterised the products of ‘Nam Dokmai’ and ‘Chok Anan’ fruits with RPI levels between 3 and 4. Conversely, fruits cv. ‘Kaew’ of RPI levels above 6 generally yielded products inferior in sensory acceptance and β-carotene contents, while superior product quality was found at higher RPI levels than for the other two cultivars.     

Effects of calcium chloride and calcium lactate applications with osmotic pretreatment on physicochemical aspects and consumer acceptances of dried papaya

This study explored the effects of calcium chloride (CaCl₂) and calcium lactate (Ca‐L) pretreatments prior to osmotic dehydration on physicochemical characteristics and consumer acceptance of dried papaya. Three different calcium concentrations [0.5, 1.5 and 2.5% (w/v)] were applied to samples before they were soaked in a 30 °Brix sucrose solution and subsequently dried at 70 °C. The results showed that the dried samples treated with calcium exhibited significantly lower moisture content, water activity, apparent density and shrinkage, while volume was higher when compared to the control. Calcium applications did not obviously influence sugar content of samples and maintained the quality of dried papaya in terms of colour and textural characteristics. Calcium chloride at 2.5% (w/v) was found to particularly impart undesirable bitterness to the dried papaya. In contrast, using 2.5% (w/v) Ca‐L provided the best acceptance scores. Thus, the use of Ca‐L could be an alternative to CaCl₂ in the pretreatment of fruits prior to drying as it offers improved quality.     

Effect of osmotic dehydration with different osmosis agents on water status,texture properties,sugars, and total carotenoid of dehydrated yellow peach slices

The water status, texture properties, sugars, and total carotenoid of dehydrated yellow peach slices pretreated with or without osmotic dehydration (OD) combined with heat pump drying were studied. In this study, different osmotic agents were used, namely, sucrose and isomaltooligosaccharide (IMO) with 30 °Brix for 1, 3, and 5 h. Results showed that the dehydrated samples pretreated by sucrose-OD with the best shape and cell structure showed lower hardness compared to the dehydrated yellow peach slices with IMO-OD pretreatment and without OD pretreatment. Notably, the highest total carotenoid content was found in dehydrated yellow peach slices pretreated by IMO-OD, followed by samples without OD, and samples with sucrose-OD pretreatment. In addition, the lowest a_W (0.517) was obtained in samples with IMO-OD for 5 h, which was beneficial for storage. The assessment of water status and total carotenoid content of dehydrated yellow peach slices showed that IMO-OD pretreatment could better improve the quality of dehydrated fruits. Moreover, the use of IMO in OD treatment was a good alternative to sucrose.     

Texture and distribution of pectic substances of mango as affected by infusion of pectinmethylesterase and calcium

Fresh cut mangos were infused with pectinesterase (PME) and calcium chloride, and the effect on textural properties, distribution of pectic substance and degree of esterification was determined. Temperature gradient infusion with PME and/or calcium chloride increased gumminess and chewiness, but had no impact on hardness and adhesiveness. The distribution of pectic substances, as protopectin or alkaline soluble pectin, was approximately twice that of water‐ or chelator‐soluble pectin. The degree of esterification of water‐ and chelator‐soluble pectic substances was near 50–60%, and less than 10%, respectively. Heat‐sensitive PME inhibitor in mango was detected. The initial hardness of Kent mango was variable, and differences in distribution of pectic substances were observed. Texture of Kent mango is most likely moderated by changes in the solubility of insoluble pectin or by non‐pectin components in the cell wall. Copyright © 2004 Society of Chemical Industry     

不同加工方法对速冻水饺皮品质的影响

采用水煮、微波熟化、微波复热三种加工方法,通过物性仪测定不同熟化方式对速冻水饺皮品质的影响。结果显示:和水煮速冻水饺皮的物性指标相比,微波复热导致水饺皮的煮后强韧性降低,硬度增大,回复性降低;微波熟化水饺皮的煮后强韧性和弹性没有明显的变化,但能提高水饺皮的咀嚼度68%,回复性24%;因此微波熟化是一种可以代替水煮加工的方法。      

浓缩型和粉末型大豆磷脂对速冻水饺品质的影响

研究浓缩型和粉末型两类大豆磷脂对速冻水饺品质的影响。通过对速冻水饺的冻裂率、煮后破肚率、质构及感官评分进行综合评定,发现分别加入0.2%、0.4%、0.6%、0.8%和1.0%的浓缩大豆磷脂或粉末大豆磷脂均能降低速冻水饺的冻裂率和煮后破肚率,提高速冻水饺的感官评分,增强速冻生饺皮的硬度、弹性、内聚性和咀嚼性等质构指标。尤其添加量为0.4%时,效果最明显,浓缩型和粉末型大豆磷脂均能使速冻水饺的冻裂率降低14%;破肚率分别降低14%和12%;速冻水饺的感官评分分别提高80.5%和73.2%;速冻生饺皮的硬度分别提高79.1%和0.1%;弹性分别增强64.9%和62.3%;内聚性增加37.9%和3.98%;咀嚼性分别提高72.1%和10.9%,且添加0.4%浓缩大豆磷脂对速冻水饺质量提高更大,得到的速冻水饺的质量更好。      

和面及揉面方式对冷冻熟面品质的影响

为研究不同和面方式(真空、普通和手工)以及不同揉面方式(机器揉面、手工揉面和不揉面)对冷冻熟面蒸煮和质构特性的影响,采用低场核磁技术分析加工方法对面条中水分状态的影响,并通过高效液相色谱图分析面条内部蛋白质的变化。结果显示:采用真空和面的冷冻熟面质构性质和蒸煮特性最好,深层次结合水比例高,SDS(十二烷基硫酸钠)蛋白可提取率低,说明真空和面可以促进面筋蛋白的交联,使面筋形成更加充分均匀,与水分的结合更加紧密;揉面过程尤其是手工揉面可以使冷冻熟面的蒸煮特性和质构性质提高,使深层次结合水含量升高,SDS蛋白可提取率降低,说明揉面可以促进面筋蛋白与水的结合,使面筋蛋白形成更加充分。     

Review: Effect of the combined application of edible coatings and osmotic dehydration on the performance of the process and the quality of pear cubes

The objective of the present work was to evaluate the combined effect of the application of edible coatings (sodium alginate and low methoxyl pectin) and different osmotic dehydration conditions (sucrose solution: 40 and 60 °Brix, temperatures: 20 and 40°C and times: 1, 2, 4, 8 and 16 h) on pear cubes (water loss, solid gain, performance ratio, the total colour differences, mechanical properties, phenolic content and sensory analysis). The results indicated that samples coated with low methoxyl pectin and treated under 60 °Brix for 16 h at both temperatures (20 and 40°C) presented the best process performance. Statistical analysis showed that the application of the coatings resulted in greater firmness and stiffness of the pear cubes at the end of osmotic dehydration. Besides, alginate coating best preserved the phenolic content (31.4%) than uncoated (26.04%) and pectin-coated (20.77%) ones. However, total colour differences were not improved with the use of edible coatings (alginate or pectin). In terms of quality, the samples coated with both hydrogels had good overall acceptability by the evaluators and good mechanical properties. However, further studies are required to decrease the difference in colour and leaching of bioactive compounds in pear cubes due to the osmotic dehydration treatment.     

Effects of different osmo‐dehydrofreezing treatments on the volatile compounds,phenolic compounds and physicochemical properties in mango (Mangifera indica L.)

The influences of different osmotic solution pretreatments (sucrose, glucose and maltose with concentration of 45%) on the volatile compounds, phenolic compounds and other physicochemical parameters in frozen mangoes were studied. Volatile and phenolic compounds were measured using SPME/GC‐MS and HPLC method, respectively. The results revealed that compared with untreated frozen mango, some volatile compounds (e.g. alcohols, aldehydes and some terpenes and esters) increased significantly and there were more compounds identified in osmo‐dehydrofrozen samples. These changes positively affected mango aroma and resulted in higher sensory scores for osmo‐dehydrofrozen samples. In addition, data on phenolic compounds showed that dehydrofrozen samples pretreated in glucose and sucrose had higher ρ‐hydroxybenzoic acid and quercetin contents, respectively, while samples pretreated in maltose showed higher ρ‐coumaric acid and sinapic acid contents compared with untreated frozen samples. The current work indicates that osmo‐dehydrofreezing can improve the retention of phenolic and aromatic compounds in frozen mango.     

Ascorbic acid metabolism in fruits: activity of enzymes involved in synthesis and degradation during ripening in mango and guava

BACKGROUND: Ascorbic acid is a very important compound for plants. It has essential functions, mainly as an antioxidant and growth regulator. Ascorbic acid biosynthesis has been extensively studied, but studies in fruits are very limited. In this work we studied the influence of five enzymes involved in synthesis (L ‐galactono‐1,4‐lactone dehydrogenase, GalLDH, EC 1.3.2.3), oxidation (ascorbate oxidase, EC 1.10.3.3, and ascorbate peroxidase, APX, EC 1.11.1.11) and recycling (monodehydroascorbate reductase, EC 1.6.5.4, and dehydroascorbate reductase, DHAR, EC 1.8.5.1) on changes in ascorbic acid content during development and ripening of mangoes (Mangifera indica L. cv. Keitt) and during the ripening of white pulp guavas (Psidium guayava L. cv. Paloma). RESULTS: It was found that there was a balance between the activities of GalLDH, APX and DHAR, both in mangoes and guavas. CONCLUSIONS: Equilibrium between the enzymatic activities of synthesis, catabolism and recycling is important for the regulation of ascorbic acid content in mango and guava. These results have contributed to understanding some of the changes that occur in ascorbic acid levels during fruit ripening. Copyright © 2008 Society of Chemical Industry     

基于质构品质变化的芒果果粒加工工艺优化

以质构品质为评价指标,研究了不同芒果品种、成熟度、硬化剂、硬化剂浓度、硬化时间、果粒大小对芒果果粒硬化效果的影响,并通过正交实验确定芒果果粒加工工艺优化参数。结果表明:台农芒果粒的硬度、咀嚼性显著高于贵妃芒、玉芒,弹性显著高于贵妃芒、玉芒、金煌芒。青熟、完熟芒果果粒硬度显著高于过熟芒果。乳酸钙处理组的芒果果粒硬度显著高于氯化钙、海藻酸钠处理组。正交实验结果表明,以完熟台农芒为原料,以乳酸钙为硬化剂,影响果粒硬度的主要因素是果粒大小与硬化剂浓度,适宜芒果果粒加工的优化工艺为:果粒大小为1.5 cm×1.5 cm×1.5 cm,硬化剂浓度为0.04 g/mL,硬化时间为2 h。在该条件下,芒果果粒的硬度为525.17 g。     

Sponge cake microstructure,starch retrogradation and quality changes during frozen storage

The effect of frozen storage (6 months) on the microstructure (microscopy, flatbed scanning and image analysis), quality (texture, moisture and specific volume) and starch retrogradation of the cake crumb were evaluated. After 2 months of storage, texture (firmness, cohesiveness and resilience) was significantly (P < 0.05) affected and starch retrogradation was observed, while by the fourth month, the crystallinity increased and crumb fractures were noticeable. Additionally, the shrinkage of starch granules was observed as the starch circularity (Sc) values significantly decreased (P < 0.05) by the sixth month of storage. Although structural changes were not detected by image analysis, it was demonstrated that cake microstructure damage is related to physical changes because the Sc was significantly correlated (P < 0.05) with moisture and specific volume and therefore with the cake quality and texture. Moreover, sugar re‐crystallisation occurred during frozen storage, and it was significantly correlated (P < 0.05) with the deterioration in cake quality.     

黑豆豆乳添加量对Mozzarella奶酪成熟过程中品质的影响

在牛乳中添加不同的黑豆豆乳,研究不同的黑豆豆乳添加量对Mozzarella奶酪在成熟0 d、30 d、60 d、90 d时的水分活度、pH、质构、色泽、蛋白质降解等品质指标变化的影响。结果显示,随着黑豆豆乳添加量在2%～6%范围内的增大,奶酪的水分活度不断增大,pH不断降低,奶酪的硬度、弹性、粘附性、咀嚼性增加,奶酪的明亮度（L*值）下降,红度（a*值）和黄度（b*值）增加,而加入黑豆豆乳的奶酪在成熟过程中蛋白质降解与对照奶酪相似。综合各个指标,在牛乳中加入4%黑豆豆乳条件下制作的黑豆豆乳牛乳奶酪,既有独特的风味,同时奶酪具有较好的色度、质构、蛋白降解等指标特性。     

Changes in volatile composition during fruit development and ripening of ‘Alphonso’ mango

BACKGROUND: Volatile blends of five developing and five ripening stages of mango (Mangifera indica L. cv. Alphonso) were investigated along with those of flowers and leaves. Raw and ripe fruits of cv. Sabja were also used for comparison. RESULTS: A total of 55 volatiles belonging to various chemical classes such as aldehydes, alcohols, mono‐ and sesquiterpene hydrocarbons, lactones and furanones were identified. In all Alphonso tissues monoterpenes quantitatively dominated, with 57–99% contribution; in particular, (Z)‐ocimene was found in the highest amount. Ripeness was characterized by the de novo appearance of lactones and furanones in the blend of monoterpenes. Sabja was distinguished by the abundance of monoterpene hydrocarbons in the raw fruit, and that of sesquiterpene hydrocarbons and their derivatives in the ripe stage. CONCLUSION: Various stages of the Alphonso fruit during transition from flower to ripe fruit are characterized by unique volatile signatures that are distinguished from each other by the qualitative and quantitative appearance of different volatile compounds. Thus volatiles can be highly informative markers while studying the development and ripening of mango. Copyright © 2009 Society of Chemical Industry     

面团冻藏对陕西Biangbiang面条品质变化的影响

该研究以高筋小麦面粉制作面团,分析-18℃ 下不同冻藏时间(0、5、10、20、30 d)对面团的流变学特性,以及冻藏后制作的Biangbiang面条的可冻结水含量、晶型结构、蒸煮特性、质构特性及微观结构的影响.结果表明,面团的黏弹性随着冻藏时间的延长逐渐下降;面团冻藏30 d后制作的Biangbiang面条中可冻结水...     

Effect of NaCl on textural changes and protein and lipid degradation during the ripening stage of sufu,a Chinese fermented soybean food

Sufu is made by solid state fungal fermentation (using Actinomucor elegans) of tofu, followed by salting and maturation in dressing mixtures containing salt, alcohol and various other ingredients. NaCl in dressing mixtures strongly affected the changes in textural properties and the hydrolysis of protein and lipid of sufu. Higher salt contents (14% w/w) resulted in increased hardness (+100%) and elasticity (+18%) and reduced adhesiveness (?30%). Hardness and elasticity could be used to judge the extent of sufu ripening. SDS‐PAGE showed the disappearance of all protein subunits at 80 and 110 g kg^?1 salt content; however, some protein subunits were still detectable at 140 g kg^?1 salt content after 60 days of ripening. Higher ratios of free amino nitrogen to total nitrogen (FAN/TN = 0.4–0.45) and free amino acids to crude protein (FAA/CP = 0.24–0.26) were observed in sufu with lower (80 g kg^?1) salt content. FAN/TN and FAA/CP in white sufu (obtained with dressing mixtures containing only salt and alcohol) were higher than those in red sufu (obtained with dressing mixtures containing angkak or kojic red rice) owing to different dressing mixture compositions. Increases in free fatty acids (FFA) were also observed during ripening. FFA levels in sufu with lower salt content increased rapidly during the first 30–40 days and then increased slowly, probably resulting from the formation of fatty acid esters. Lowering the salt content (80 g kg^?1) can shorten the ripening time to 40 days, which is of benefit to manufacturers. However, sufu will spoil, ie undergo souring, during the ripening stage at salt contents of 50 g kg^?1 or lower. Copyright © 2003 Society of Chemical Industry