Influence Of Blanching Research Articles

The Influence of Blanching and Drying Process Towards Extract of Bioactive Compounds in Solanum Torvum and its Antioxidant Activities

Eggplant Pokak has potential to be developed into processed products that contain antioxidant biocytic compounds. The purpose of this research was to analyze the bioactive compounds in Solanum torvum which were treated with blanching and various types of drying. The research method used quantitative analysis of antioxidant compounds against the treatments tested. The results showed that the analysis of bioactive compounds which had the best results was Solanum torvum fruit which pretreated by blanching process for 10 minutes at 70 ºC then dried by vacuum method at 50 ºC for 14 hours. The bioactive compounds content from Solanum torvum flour were Vitamin C 3.24 %, total phenol 85.16 mg·g-1, tannin 2.12 mg·g-1, flavonoids 9.10 mg·g-1, and antioxidant activity 92.1 %.

Influence of blanching and frozen storage on quality characteristics of vegetable soybean (Glycine max)

Effect of blanching on freezing and quality attributes during frozen storage of vegetable soybean [Glycine max (L.) Merrill] was investigated during 2015–16 at ICAR-RCER, RC Ranchi. Seeds were blanched for 5 and 10 min in boiling water, steam and microwave. Freezing was carried out at -20oC and stored in frozen condition (-18oC) for 12 months. Quality attributes such as drip loss, ascorbic acid, chlorophyll, hardness, colour, microbiological status and sensory trait were examined. Green seeds (58.3%) were recovered from harvested vegetable soybean pod, in which 54.8% were good seeds and 3.5% were physically damaged. Drip loss of frozen samples was between 3.68% and 5.54% during the storage period. A loss of 35.7% was found in ascorbic acid after blanching that further reduced to 71.9% after 12 months of frozen storage. Chlorophyll reduced to 21.9% due to blanching and freezing that furtherdecreased to 42.4% at the end of storage. Blanching treatments did not show significant variation in hardness while losses of hardness were significant during storage. Colour retention was better in samples blanched in boiling water or steam. Bacterial and fungal count at the end of 12 months frozen storage suggested that samples were microbiologically safe to consume. Sensory examination revealed that 10 min blanching either in boiling water or in steam was more acceptable vis-à-vis samples blanched in microwave.

Influence of Blanching and Drying Air Temperature on Drying Kinetics of Banana Slices

Influence of Blanching and Drying Air Temperature on Drying Kinetics of Banana Slices

Oil–free potato chips produced by microwave multiflash drying

The present work is about the production of oil-free potato snacks using successive cycles of microwave heating-vacuum pulses and was therefore called microwave multiflash drying (MWMFD). Drying kinetics and product physical properties were assessed, as well as the influence of blanching (BL) and vacuum impregnation (VI) as pre-treatments before drying. The drying curves presented three periods: a heating period, a high drying rate period promoted by the vacuum pulses, and a falling rate period. The drying time of 400 g of potatoes was approximately 60 min, reducing gradually the microwave power from 800 to 200 W. The vacuum-pulse step changed the material, resulting in a porous and fragile microstructure, characteristic of crispy products, as well resulting in a product surface with a golden yellow color. BL and VI combined was the best pre-treatment for obtaining very crispy oil-free potato snacks. The results of this study indicated MWMFD as a suitable process to produce crispy potato snacks, free of oil, in only 60 min.

Influence of Blanching on the Production of Pectinases from Banana Peels by <i>Aspergillus niger</i>

Pectinases are enzymes that break down pectin, a polysaccharide found in plant cell walls into simpler molecules. They are commonly referred to as pectic enzymes. Influence of blanching was determined on the production of pectinases from banana peels by Aspergillus niger. Banana peels were subjected to blanching with cold 5% NaCl. Aspergillus niger isolated from decaying banana peels using potato dextrose agar (PDA) were screened for the production of pectinases by examining the isolates with the largest zone of clearance. Solid state fermentation (SSF) and submerged fermentation (SMF) were carried out with the banana peels as the substrate (carbon source) using the Aspergillus niger with the largest zone of clearance. The result revealed that SSF has the highest yield of polygalacturonase and pectin lyase production and both were produced on day 3 of the fermentation having values of 7.5544U/mL and 22.3214U/mL respectively. It was observed that yield of production was generally higher in blanched banana peels when compared with unblanched banana peels. Subjection of banana peels to blanching with cold NaCl solution in solid state fermentation gave higher levels of pectinases activity when compared with banana peels that were not treated at all. Therefore blanching of banana peels for pectinases production is of great importance.

Influence of blanching and drying methods on molecular structure and functional properties of elephant foot yam (Amorphophallus paeoniifolius) flour

Abstract The purpose of the present study was to investigate the effect of solar and freeze drying approaches on the physico-chemical, thermal and pasting properties of raw and blanched elephant foot yam (Amorphophallus paeoniifolius). Morphologically, starch granules in blanched and solar dried flours were observed as heterogeneous and collapsed while raw freeze dried flour was the least affected. The amylose content was highest in IDSB (29.50%) followed by DSB, FDB, FDR, and IDSR while lowest in DSR (15.83%). Freeze dried flours had higher whiteness (L*) than solar dried flours. Freeze dried raw flour (19.38%) had the highest solubility while freeze dried blanched flour (8.39%) exhibited the lowest. Freeze dried flour samples had the least swelling power. Direct solar dried (raw and blanched) flours showed relatively lower syneresis than freeze dried flours. The differences in pasting profile, textural analysis and relative crystallinity could be explained as a function of variation in amylose content and the drying method employed. The solar dried flours had higher T0, TP, and TC than the freeze dried flours (raw and blanched). The ΔH gel value of flours was highest for freeze dried raw flour and lowest for direct solar dried blanched flour.

The influence of blanching, anti-browning agent and processing time on some physico-chemical properties and appearance of green peppers (Capsicum sinensis) during canning

Central Composite Rotatable Design (CCRD) was used to generate twenty combinations of these factors: blanching time, processing time and sodium metabisulphite concentration. The optimized conditions were then adapted for the canning process of green pepper. Blanching time ranged from 0-1 min whereas processing time and sodium metabisulphite concentration ranged from 10-30 min and 0-0.2%, respectively. The canned products were analyzed for physico-chemical qualities using standard analytical methods. Results obtained from various physicochemical analyses showed variable trends and influences of the linear, quadratic and exponential interactions on the measured quality indices such as pH of the drained liquid, drained weight of the canned product, leached solids and colour of the canned products. The results showed significant (p≤0.05) quadratic effect of sodium metabisulphite as well as linear effect of blanching time on the drained weight of the canned green pepper. Generally, the pH of the medium decreased (increased acidity) with increasing processing time, which was also positively associated with the extent or amount of leaching. Additionally, all three factors were observed to have affected (to variable extent) the colour of the canned products. Blanching and processing times also affected the degree of browning. There was a strong significant (p≤0.05) influence of the quadratic factors of blanching time, processing time and sodium metabisulphite concentration on the colour properties (a-values, b-values and Lvalues) of the canned products. Statistical analysis showed significant (p≤0.05) linear effects of blanching time and sodium salt concentration as well as the combined effect of both factors on all the colour properties. All the studied parameters had significant regression coefficients (p≤0.05) suggesting the studied parameters contributed significantly to the observed changes. Colour of the canned products changed from green toward redness with increasing blanching time at all concentrations of sodium metabisulphite. Optimal processing combination of 0 min blanching time, 10 min processing time and sodium metabisulphite concentration of 0.2% produced a highly acceptable canned pepper product with preferred physico-chemical and appearance properties.

Influence of blanching, freezing and frozen storage on physicochemical properties of broad beans (Vicia faba L)

We evaluated the effects of blanching, freezing and frozen storage (5 months at −18 °C) on the physicochemical properties of broad beans at milk maturity stage. Times for minimal blanching (120 s) and over-blanching (180 s) were determined in a preliminary experiment. Frozen storage for five months caused 31% and 34% total chlorophyll degradation in minimally blanched and overblanched beans, respectively. Color differed greatly between fresh and blanched then frozen beans. Blanched then frozen samples showed increased firmness compared with fresh beans and decreased firmness following frozen storage, regardless of the blanching time. In sensory evaluation of cooked beans, a significant reduction in texture was found in overblanched beans compared with unblanched beans. These findings demonstrate that blanching adversely affects this vegetable and that deterioration reactions do not cease during frozen storage.

Influence of Blanching and Grinding Process with Hot Water on Beany and Non‐Beany Flavor in Soymilk

A total of 8 beany odor-active compounds and 4 non-beany aroma-active compounds of traditional soymilk were identified through dynamic headspace dilution analysis (DHDA) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS). To eliminate the beany flavors, soymilk was processed with hot water blanching and grinding for 2, 4, 6, 8, and 10 min with a temperature between 80 and 100 °C. A total of 5 beany odor-active compounds and 3 non-beany aroma-active compounds of this soymilk were analyzed by headspace solid phase microextraction (HS-SPME). As a result, lipoxygenase (LOX) activity gradually decreased by hot water treatment with time, and with the decrease of Lox activity, the 5 beany odor-active compounds and 3 non-beany aroma-active compounds were significantly decreased. However, the reduction in non-beany flavor compounds was smaller than for beany odor compounds. Therefore, a balance between beany and non-beany flavors can be reached in soymilk. When the soaked soybeans were blanched and ground with hot water for 2 to 6 min, the LOX activity was between 38% and 57% of the beginning activity. For these processing times, the non-beany compounds could be largely maintained. The ratio of the total peak area of the 3 non-beany aroma compounds and 5 beany flavor compounds was between 0.07 and 0.12, and the sensory scores of the aromas were higher than that of the off-flavors. Practical Application: Beany flavors in soymilk could be reduced with hot water blanching and grinding at temperature above 80 °C. However, the treatment of hot water blanching affected the non-beany aromas of soymilk. A suitable blanching and grinding time is necessary to achieve a balance of soymilk flavors.

Influence of blanching and low temperature preservation strategies on antioxidant activity and phytochemical content of carrots, green beans and broccoli

The objective of this study was to investigate the effect of blast freezing and blanching in combination followed by chilling, on the antioxidant activity (ARP), phenols, ascorbic acid and colour of broccoli, carrots and green beans. No significant changes ( p > 0.05) in ARP of blanched frozen (BLFR) broccoli, carrot and green beans were observed. In contrast, UBFR (unblanched frozen) treatments caused a significant decrease ( p < 0.05) in ARP and ascorbic acid content of vegetable samples. BLFR treated samples had better retention of antioxidant activity and ascorbic acid as compared to UBLR counterparts at chill storage (4 °C) for 7 days. However, no significant changes were observed in phenol content for all vegetables. Ascorbic acid decreased exponentially for both blanched and unblanched samples. The reaction rate constant ( k) increased from 1.06 × 10 −1 day −1 to 1.17 × 10 −1 day −1 for blanched and unblanched broccoli florets and from 4.6 × 10 −3 day −1 to 1.98 × 10 −1 day −1 for blanched and unblanched carrots during 7 days storage. Result presented here indicates greater stability of nutritional parameters for BLFR samples compared to UBFR samples during 7 days storage at 4 °C for all vegetables.

Influence of blanching and slice thickness on drying characteristics of leek slices

The effect of blanching and slice thickness on drying characteristics of leek was studied. Drying experiments were performed in a cabinet dryer. Drying time decreased with blanching, but it increased considerably with increased slice thickness of leek. Besides, predrying treatment such as blanching was found to improve the rehydration capacities of leek slices. The experimental drying curves obtained show only a falling rate period. In order to estimate and select the suitable form air drying curves, seven different mathematical models were applied to the experimental data. Determination of coefficient ( R 2), reduced chi-square ( χ 2) and root mean square error ( E RMS) were used for determination of the best suitable model. Among the mathematical models investigated, the logarithmic and Midilli et al. models satisfactorily described the drying behaviour of leek slices with highest R 2 and lowest χ 2 and E RMS. The effective moisture diffusivity during drying varied from 1.145 to 2.642 × 10 −10 m 2/s.

Influence of blanching and freezing broccoli (Brassica oleracea var. italica) prior to storage and cooking on glucosinolate concentrations and myrosinase activity

Glucosinolates contribute to the chemoprotective effects of Brassica vegetables. The influence of blanching and freezing broccoli, followed by storage or cooking, on its glucosinolate concentration and myrosinase activity was investigated. Myrosinase activity was reduced by 93%, while glucosinolate concentration was unaltered after blanch-freezing broccoli. Blanch-frozen Brassica retained the glucosinolate content of its fresh counterpart after storage at T = −20 °C for up to 90 days. Fresh or blanch-frozen broccoli was stir-fried, boiled, boiled and kept hot for 2 h, or left uncooked. Stir-frying retained the highest glucosinolate concentration and myrosinase activity, regardless of pre-cooking. Boiling and keeping blanch-frozen broccoli hot completely denatured myrosinase and decreased glucosinolate concentration by 42%. Aromatic and indole glucosinolates were reduced to a larger extent than aliphatic glucosinolates, especially when boiled broccoli was kept hot. The final concentration of glucosinolates in Brassica is influenced by cooking, while the myrosinase activity is modified by pre-treatment and subsequent cooking.

OSMOTIC DEHYDRATION OF MUSKMELON (CUCUMIS MELO): INFLUENCE OF BLANCHING AND SYRUP CONCENTRATION

The influence of blanching and syrup concentration on the quality parameters of osmo-air-dried muskmelon product was investigated. Fruit samples were dehydrated with sucrose solutions at 40, 50 and 60°Brix and the resulting products were analyzed for browning degree, ascorbic acid (AA) concentration and water activity. The values for all three parameters decreased as the syrup concentration increased. Blanching treatment before the osmotic processing had no effect on browning but caused a decrease in AA concentration. Osmotically dehydrated fruits showed no browning increase for at least 4 weeks at 2C. A decrease of about 60% in AA concentration was observed within the first 2 weeks at 10C. In contrast, AA loss was only observed after 2 weeks at 2C. The influence of storage time and temperature on AA retention was investigated by 2 2 factorial design. Statistical analysis of results showed that the two factors have a significant effect on AA retention. Osmotic dehydration may be an interesting alternative for processing of muskmelon as a pretreatment followed by cold storage or drying.

A proposed mechanism of high-temperature puffing of potato. Part I. The influence of blanching and drying conditions on the volume of puffed cubes

Potato cubes were blanched and partially dried in a cabinet drier prior to puffing in a Torbed 500, high-temperature fluidised bed drier. It was established that formation of a partially dried layer (PDL) on the surface of the cubes was necessary to achieve puffing. The influence of blanching and drying conditions on this layer was investigated. It was concluded that blanching for 2 min in water at 100°C followed by drying in air at 90°C for 40 min resulted in the maximum increase in volume of the puffed cubes.

A proposed mechanism of high temperature puffing of potato. Part II. Influence of blanching and initial drying on the permeability of the partially dried layer to water vapour

The permeability of the surface layer, the partially dried layer (PDL), to water vapour was measured. It was found that blanching reduced the permeability of the surface layer to water vapour. This was shown to be due to gelatinisation of starch on the surface. This finding was confirmed by examining the structure of the surface layer using stereomicroscopy and variable pressure scanning electron microscopy.

SHRINKAGE OF APPLE DISKS DURING DRYING BY WARM AIR CONVECTION AND FREEZE DRYING

ABSTRACT Volumetric and thickness shrinkage evaluated by direct measurement and n-heptane displacement were determined during convective and freeze drying of Golden delicious apples. For convective drying, the influence of blanching and diameter/thickness ratio of the apple disks used were analysed at different levels of moisture content under constant conditions. It was found that shrinkage of dried samples, both by convection and by freeze-drying, is anisotropic to a level which depends on sample geometry (ratio diameter/thickness) used. Blanching did not affect shrinkage results. Based on results obtained a new model to predict bulk density of materials during drying is proposed, showing a better fit to experimental data than previous models reported in the literature. This model was further used to predict changes in apple porosity during drying.

An Electron Microscopy Study on the Texture of Fresh, Blanched and Sterilized Green Bean Pods (Phaseolus vulgarisL.)

The influence of blanching and sterilization on the tissues of green-bean pods (Phaseolus vulgarisL.) was studied using scanning (SEM) and transmission electron microscopy (TEM). Fracture planes were examined by SEM, showing that the outer and inner parenchyma tissues had a different contribution to texture after heating. After heating at 90 °C the outer parenchyma tissue fractured along the middle lamellae, whereas the inner parenchyma tissue fractured through the cells. After sterilization, all cells could be easily separated along the middle lamellae, but the adhesion between adjacent cells was more retained in the inner parenchyma. By using TEM, the middle lamellae were shown to be more pronounced in the outer parenchyma tissue. A proposed causal relationship between the difference in middle lamella ultrastructure and the different fracturing behaviour of the two tissues is discussed. Blanching and sterilization in general caused partial degradation of the cell wall and middle lamella as indicated by swelling and loss of contrast. However, differences between the middle lamella of the inner and outer parenchyma tissues remained evident after these heat treatments. Cellulose microfibrils were visualized after extraction of the matrix materials from the cell walls and seemed to be unaffected by the heat treatment.

Influence of pH treatment on pectic substances and firmness of blanched carrots

The influence of blanching and the gradual reduction of pH within carrot tissue from 6.2 to 3.9 by acetic acid infiltration was studied. Maximum firmness of about 86 N was observed at pH 4.4, while at higher or lower pH firmness was about 58 N. Galacturonic acid content, and neutral sugars of the water-soluble pectic, EDTA and alkaline-soluble pectin fractions were assessed after the pH treatments. EDTA-soluble pectin increased after blanching at all pH values, but less so at pH 4.4. Total pectin decreased to a lesser extent at pH 4.4 than at either higher (6.2) or lower (3.9) pH values. Lower amounts of soluble pectin were found at pH 4.4 than in the control. A significant positive correlation was found between firmness and the alkali-soluble pectin content.

Carotenoid and anthocyanin contents of papaya and pineapple: Influence of blanching and predrying treatments

Effects of blanching and predrying treatments on the stability of carotenoids and anthocyanins in papaya ( Carica papaya var Subang) and pineapple ( Ananas comosus var Mauritius) were investigated. Carotenoids which are relatively heat-stable showed higher retention than anthocyanins after blanching and drying in both of the fruits. Carotenoids and anthocyanins decreased progressively in pineapple and papaya as the blanching temperature and time increased. Pretreatment with sodium metabisulphite prevented carotenoids from oxidation but caused bleaching of anthocyanins. Orthophosphoric acid, which changed the colour intensity of anthocyanins, showed no effect on carotenoids. Carotenoids were more protected in a system with higher moisture retained by glycerol and sugar. Anthocyanins, however, were stable only within a certain range of moisture contents.

Effect of sulphur dioxide and blanching on the stability of carotenoids of dehydrated carrot

AbstractThe influence of blanching and sulphiting of carrot on the stability of carotenoids of dehydrated carrot was evaluated. The carotenoid content of untreated and treated carrots was measured after dehydration and during storage of dehydrated carrot at 37°C. Sulphiting was found to have a marked effect on the stability of carotenoids of both unblanched and blanched carrots during dehydration and storage at 37°C. The effectiveness of sulphur dioxide was reduced by increasing blanching time to over 1 min, the period in which the carrot becomes just adequately blanched. Even 9621 μg−1 SO2 in over‐blanched carrot was not as effective as less than one‐quarter of this concentration in carrot that had been just adequately blanched. The combination of sulphiting, and blanching to a level sufficient to inactivate peroxidase activity, is considered to be the most effective method for enhancing the storage life of the product, and optimisation of the blanching process is highly desirable in order to gain the maximum benefit from the SO2 treatment.