Degree Of Browning Research Articles

Effect of Freezing Pretreatment on the Processing Time and Quality of Black Garlic

AbstractBecause freezing treatment can destroy the cell structure of garlic, we investigated the effect of freezing pretreatment on black garlic processing with the traditional processing method as contrast. Results showed that freezing for 30 h had the greatest impact on the reducing sugar content. The control garlic processing 21–24 days had the best quality. Freezing pretreatment can affect the black garlic quality through the browning degree, reducing sugar content, amino‐N content, total phenolic content and 5‐hydroxymethyl‐2‐furaldehyde (5‐HMF) levels. The freezing garlic had a faster color change than control samples. When the processing ended, the reducing sugar content, total phenols content and 5‐HMF content of freezing pretreated garlic were increased by 51.88, 58.54, 25%, respectively, compared with the control samples. The amino‐N content of freezing‐pretreated garlic decreased 50.97% compared with the control one. The results indicated that freezing pretreatment can promote the generation of functional materials.Practical ApplicationsAlthough garlic has been used worldwide as food or herbal supplement, some people feel discomfort because of its strong pungent odor. Black garlic is one of the garlic‐processed products, eliminating its stimulating odor. However, the quality of black garlic products on the market is varied and the processing time is long. As is known, freezing is widely used to destroy cell structure. In the present study, the use of freezing pretreatment in black garlic processing can promote the generation of functional materials and significantly reduce processing time from 60–90 to 22 days. These provided potential method to the black garlic processing.

Influence of air drying properties on non-enzymatic browning, major bio-active compounds and antioxidant capacity of osmotically pretreated papaya

This study aimed to investigate the effect of air drying parameters such as temperature, specific humidity and velocity, on non-enzymatic browning behaviour and on bio-active compounds and antioxidant properties of osmotically pretreated papayas. Convection drying was conducted under through-flow mode at four temperatures (50, 60, 70, 80 °C), three air velocities (0.2, 0.5, 0.7 m/s) and two specific humidity levels (10, 25 g/kg dry air). Higher drying temperatures resulted in a significant decrease in moisture content and polyphenol oxidase activity, while degree of browning and 5-hydroxymethylfurfural increased. The antioxidant activity and total phenolic compounds increased with temperature and as well with decreasing air velocity. In contrast, specific humidity did not have a major effect on quality attributes of dried samples, except for carotenoid contents. This study has shown that drying parameters can decompose and/or enhance carotenoids contents in dried papayas. To obtain the product with highest level of bio-active compounds and lowest possible melanoid formation, treatment with temperature of 70 °C, specific humidity of 10 g/kg dry air and velocity of 0.2 m/s proved to be the most suitable option. Based on these results, optimization of the process, particularly drying temperature, should be considered with respect to preserving product colour and biochemical properties.

Comparison of image analysis methods to evaluate the degree of browning of fresh-cut lettuce

Digital image analysis was used to detect changes in browning of fresh-cut lettuce. Fresh-cut lettuce was divided into the 4 treatment groups of dipping in distilled water (control group); ultrasound treatment for 90 s in distilled water (US); blanching for 90 s at 45°C (BC); and blanching after ultrasound treatment (US+BC). The degree of browning was measured using image analysis, colorimetry, spectrophotometry, and visual assessment. Using image analysis, the US+BC treatment group showed the smallest browning area and lowest b* value. Correlation between visual assessment and image analysis for evaluation of the area of browning was the highest (0.9592), followed by the b* value of image analysis (0.9527). The lowest correlation coefficient (0.6962) was observed between visual assessment and the b* value using colorimetry. Image analysis can be used as a method for evaluating browning in fresh-cut lettuce.

자건 멸치의 품질 개선에 대한 산성 전해수의 영향

The quality improvement of the boiled-dried anchovy treated with acidic electrolyzed water (AEW) was investigated. The L value was higher in the anchovy treated with AEW than in the control. Moreover, its ΔE value was 5.08 higher than that of the control. The lipophilic browning degree was also higher than the hydrophilic degree. The degrees of calcium absorption of the control and anchovy treated with AEW were 10.77% and 12.61%, respectively. During their storage in the different conditions (five weeks in 20°C, ten weeks in 4°C, and five months in –20°C), the lipophilic browning degree of the anchovy treated with AEW was significantly lower than that of the control at the 20°C storage. The volatile basic nitrogen (VBN) content gradually increased as the storage period increased. During the 20°C storage, the content of the anchovy treated with AEW was lower than that of the control. The lipid peroxide contents increased with the storage periods, regardless of the temperature, but the content of the anchovy treated with AEW was lower than that of the control. These results indicate that AEW treatment can improve the color quality of boiled-dried anchovy and reduce its VBN and lipid peroxide contents.

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.

Dynamics of total phenolic content in different apple tissues and genotypes: impacts and relevance for breeding programs

The content and quality of phenolic compounds in apple pulp, peel, and leaves constitute important nutraceutical properties of apples in the human diet and are equally important to plant ecology. Moreover, increased understanding of the dynamics of polyphenol synthesis in different apple tissues of different genotypes may assist in apple breeding programs. Thus, the present study aimed to analyze the levels of total phenolics in apple pulp, peel, and leaves from cultivars Aori27, Elstar, Fuji, and Mellow at harvest time. Significant differences in the total phenolic content were found between cultivars for all evaluated tissues, but the differences between cultivars were not consistent among tissues, indicating the potential existence of tissue-specific genetic regulation mechanisms, as well as cultivar-specific dynamics. Additionally, tissues of two cultivars, Fuji and Mellow, were analyzed in the last three months of fruit development, showing a similar overall evolution in the phenolic concentration for all tissues, but some notable cultivar-specific characteristics for apple pulp and peel. These results are relevant for apple breeding when we consider as selection criteria the nutraceutical properties of apple polyphenols, the speed and degree of pulp enzymatic browning, and the physiological and agro-ecological roles of polyphenols in different organs and tissues of apple trees.

Study on Polyphenol Oxidase Activity in Different Parts of Purple Sweet Potato

The basic study on activity of polyphenol oxidase (PPO) from different purple sweet potato (PSP) parts was mainly carried out here. The PPO activity and browning degree (BD) of PSP peel were higher than those of inner-tissue and intact sweet potatoes. The relativity between them was positive, and relativity coefficient was 0.9895. The activity of PPO extracted from sliced PSP increased initially and decreased afterwards, with the highest activity of PPO on the third day during storage. And BD increased very quickly as time went by, especially in the first three days. The relativity between PPO activity and BD was negative, and relativity coefficient was-0.8747.

Kinetics of Browning, Phenolics, and 5-Hydroxymethylfurfural in Commercial Sparkling Wines

We analyzed the degree of browning (absorbance at 420 nm), the phenolics, and the 5-hydroxymethylfurfural (5-HMF) content in six sparkling wines series kept at three temperatures (4, 16, and 20 °C) for over 2 years. Caffeic acid, trans-coutaric acid, p-coumaric acid, and 5-HMF were the compounds with the greatest correlation with browning and time. 5-HMF was the only compound that evolved linearly at all temperatures. We propose that 5-HMF is a better time-temperature marker than the A₄₂₀ parameter or phenolics, because it shows higher linearity with time at all temperatures, is more sensitive to temperature changes, and has lower variability. The kinetics of 5-HMF was studied showing a zero-order behavior. We propose mathematical models that wineries can use to predict the browning shelf life of their sparkling wines as a function of the storage time and temperature.

Physicochemical Properties of Whole Fruit and Sensory Quality of Fresh-Cut Apples Pre-Treated with 1-Methylcyclopropene (1-MCP)

Apple fruit quality is an important factor in minimally processed or fresh-cut slices. Ethylene action inhibitor, 1-methylcyclopropene (1-MCP) is used commercially to extend the shelf life of selected fruits, including apples. The present study was designed to assess the selected physiochemical properties of whole fruit and sensory attributes of fresh-cut slices from three 1-MCP treated apple cultivars (Jonagold, Empire, and Mutsu) that were stored for 3 months in air or 6, 9, and 12 months in controlled atmosphere. Apples and fresh-cut slices were evaluated for selected quality characteristics at 3-month intervals. Generally, the 1-MCP treatment resulted in firmer fruit and lower pH, whereas it had no or minimal effect on fruit skin color and total soluble solids. Titratable acidity values decreased in both control and 1-MCP treated apples, the only exception being 12-month controlled atmosphere stored apples that showed an increase. At each 3-month interval, fresh-cut slices (after 10-day storage at 4°C) were evaluated by a 9-member trained panel for “difference from control” on a 0–8 scoring scale; the results of these evaluations showed relatively small “difference from control” scores for the degree of browning, texture, and flavor. At the 9-month storage, a 114-member consumer panel evaluated the appearance, texture, flavor, and overall acceptability of fresh-cut slices on a 1–9 hedonic scale. Except for Jonagold slice flavor, slices from 1-MCP treated fruit exhibited similar or higher sensory scores. The overall acceptability scores were 6.78, 7.12, and 7.18 for slices from Jonagold, Empire, and Mutsu apples, respectively.

Effect of combining conventional frying with radio-frequency post-drying on acrylamide level and quality attributes of potato chips

In conventional manufacturing of potato chips, achieving an extremely low moisture content (2% by weight) in the final product necessitates prolonged exposure of potato slices to high oil temperatures. This promotes acrylamide formation and causes an exponential increase in acrylamide level toward the end of the frying process. In this regard, frying potato slices partially in hot oil followed by a radio-frequency (RF) drying treatment to selectively heat the remaining moisture appears to be a viable approach in terms of limiting acrylamide formation. RF post-drying of partially fried potato slices resulted in lower acrylamide levels (80.4 ng g(-1) for control, 59.4 ng g(-1) for RF post-dried potato slices partially fried for 95 s, 54.8 ng g(-1) for RF post-dried potato slices partially fried for 80 s). This process modification also led a to 12% reduction in oil content in the final product. According to instrumental analysis results, RF post-dried samples had lower hardness and a slightly lower degree of browning in comparison to control. No significant difference (α = 0.05) was found between samples in terms of sensory characteristics. Results demonstrate that RF post-processing may be an effective strategy for minimising acrylamide levels of potato chips without adversely affecting quality attributes.

Effects of high hydrostatic pressure and high temperature short time on antioxidant activity, antioxidant compounds and color of mango nectars

Abstract High hydrostatic pressure (HHP, 600 MPa/1 min) and high temperature short time (HTST, 110 °C/8.6 s) treatments of mango nectars were comparatively evaluated by examining their effects on antioxidant activity, antioxidant compounds, color, and browning degree (BD) immediately after treatments and during storage of 16 weeks at 4 and 25 °C. Steam blanching was used prior to HHP and HTST to inactive endogenous enzymes. Results showed that antioxidant capacity (FRAP assay), L -ascorbic acid, sodium erythorbate, total phenols, total carotenoids, the redness ( a *), the yellowness ( b *), and BD changed insignificant after HHP or HTST treatment. The lightness ( L *) exhibited a significant decrease in HTST-treated mango nectars, while no significant changes in HHP-treated samples. After 16 weeks storage at 4 and 25 °C, there were significant changes in antioxidant activity, antioxidant compounds, color, and BD of mango nectars, whereas differences between HHP- and HTST-treated samples were not significant except for the decrease in L -ascorbic acid and sodium erythorbate, which was more pronounced in HHP-treated samples. Kinetic data of changes in L -ascorbic acid, sodium erythorbate, total phenols, and total carotenoids during storage fitted well into a combined model for both HHP- and HTST-treated samples. Industrial relevance Mango ( Mangifera indica L.) is one of the important tropical fruits, and its processed products are of high commercial and economic importance. This research paper presents a comparison on HHP- and HTST-treated mango nectars, and also provides information about storage stability of antioxidant activity, antioxidant compounds, and color of mango nectars. The available data would provide technical support for the evaluation and application of HHP or HTST in the mango nectar industry, and also for the establishment of criteria for commercial production of high quality mango nectars with safety requirements.

Hyperbaric storage at and above room temperature of a highly perishable food

Hyperbaric storage at naturally variable room temperature (RT) conditions (18–21 °C) and above (30 °C) was evaluated as a possible new food preservation method, regardless of temperature. Preservation of watermelon juice (used as a case study of a highly perishable food) at RT and 5 °C at atmospheric pressure was compared to preservation under 100 MPa at RT. After 8 h of hyperbaric storage at 100 MPa, the initial microbial loads of the watermelon juice were reduced by 1 log unit for total aerobic mesophiles, and 1–2 log units for Enterobacteriaceae and yeasts and moulds, to levels of about 3 log units for the former and below the detection limit for the latter, and remained thereafter unchanged up to 60 h. Similar results were obtained at 30 °C at 100 MPa after 8 h. At atmospheric pressure at RT (24 h) and 30 °C (8 h), microbial levels were already above quantification limits and unacceptable for consumption. Furthermore, pressure attenuated the increase in titratable acidity verified at atmospheric pressure, but caused higher colour changes, especially a higher lightness and a lower browning degree. Post-hyperbaric storage at 5 °C revealed an extended shelf life, as an additional benefit of hyperbaric storage. These results show that hyperbaric storage is a very promising food preservation methodology.

전처리 및 포장방법이 냉풍감압건조 복숭아의 품질에 미치는 영향

This study was conducted to investigate the effects of pretreatment and different packaging methods on the physicochemical properties of cold vacuum-dried peaches. All the dried peach samples were stored such as gas substitution, vacuum and passive packaged with polyethylene (PE) film and oriented polypropylene (OPP)/aluminum (Al)/PE film at for 50 days. The weight change, pH, soluble solids content, titratable acidity, soluble solid-acid ratio (SS/TA), delta E, browning degree and phenolic compounds were analyzed. The weight change and pH were lower in the 0.1% vitamin C-treated group and were significantly lowest in the vacuum-treated OPP/AL/PE. The soluble solids content and the SS/TA were higher in the non-treated groups than in the vitamin C-treated groups. According to the packaging methods, the values were higher in the vacuum, gas and passive package, in that order. In addition, the browning degree and the delta E value were lower in the pretreated groups and significantly lowest in the vacuum-treated OPP/AL/PE with 0.1% vitamin C group. The phenolic compounds were high for the pretreated groups, according to the packaging methods (vacuum > gas> passive), and the OPP/AL/PE was significantly higher than the PE. These results suggest that different packaging materials and pretreatment methods affected the quality of the dried peaches, and the vacuum-OPP/AL/PE film packaging group showed a high quality.

Study on Browning Degree of Fresh-Cut Purple Sweet Potato and its Inhibition during Storage

The basic study on activity of polyphenol oxidase (PPO) from purple sweet potato (PSP) and its control method was mainly carried out by spectrophotometry. The PPO activity and browning degree (BD) of PSP peel were higher than those of inner-tissue and intact sweet potatoes. The relativity between them was positive, and relativity coefficient was 0.9895. The activity of PPO extracted from sliced PSP increased initially and decreased afterwards, with the highest activity of PPO on the third day during storage. And BD increased very quickly as time went by, especially in the first three days. The relativity between PPO activity and BD was negative, and relativity coefficient was-0.8747. The result indicated that the browning of fresh-cut PSP slices during storage was mainly due to PPO in it. The composite inhibitor was optimized by the orthogonal design, and the addition of 0.05% L-cysteine+0.03% phytic acid+0.3% ascorbic acid+0.3% citric acid would markedly inhibit the enzymatic browning caused by PPO and improve the quality of fresh-cut PSP slices.

Infection process of Bipolaris sorokiniana on wheat leaves is affected by silicon

The supply of silicon (Si) to wheat plants may potentiate their resistance against infection by Bipolaris sorokiniana. Considering that there is no information regarding how Si affects the infectious process of this fungus on wheat leaves, this study intended to investigate, using light and scanning electron microscopy, the effects of Si supply on the infection process of B. sorokiniana on wheat leaves at tissue level. For that, leaf segments of -Si and +Si plants were prepared. The number of necrotic brown cells and the degree of browning of necrotic cells were determined for each infection site. As results, it was found that the number of brown epidermal cells and the frequency of infection sites showing browning were significantly lower on leaves of +Si plants. On the leaves of -Si plants, an intense dissolution of the wax layer also occurred and hyphae were found inside the disorganized epidermal cells. On leaves of +Si plants, degradation of the wax layer was observed only in areas close to conidia. Within 96 hours after inoculation, a dense network of hyphae had colonized the leaf surface of -Si plants, in striking contrast to +Si plants, for which only sparse hyphae were found.

Factors Affecting the Color of Roasted Cocoa Bean

AbstractThe cacao bean of the Ivory Coast variety was convectionally roasted. The influence of parameters of air (temperature from the scope T = 110–150C, the speed of its flow v = 0.5 and 1.0 m/s, and the relative humidity = 0.3–0.8% or 2 and 5.0%) and time on the degree of browning of the cacao bean was analyzed. For the evaluation of the quality of the grain, two indicators were applied: OD460/OD525 and the F1/F3 ratio. Based on the data obtained, using the response surface methodology has optimized the process of cocoa roasting for its acceptable color.Practical ApplicationsThe process of roasting the cacao bean should contribute to achieving the acceptable physicochemical properties, such as the appropriate degree of browning of the bean. From a point of view of the technology of chocolate production, it is essential to know which factors of the roasting process will have a significant influence on the color change of the roasted cacao bean. It will allow one to predict changes in roasted bean and to select process conditions depending on quality requirements of the grain.

한약재 추출물, 가열 및 코팅 처리가 신선절단 사과의 갈변도에 미치는 영향

The effects of dip treatments of chemicals (ascorbic acid, cystein, sodium chloride, magnesium chloride, calcium chloride, histidine: 1% solution) and medicinal herbs (Pueraria thunbergiana, Angelica gigas, Dioscorea japonica, Lindera strychifolia, Cnidium officinale, Astragalus membranaceus: 1% extracts), heat shock ( water), and edible coating (albumin, dextrin, sucrose poly ester, whole soy flour: 0.5-4% solution) on the browning degree of fresh-cut `Fuji` apples were studied. Among the each treatment methods, the surface browning of fresh-cut apples was best retarded by calcium chloride dip, Astragalus membranaceus dip, heat shock, coating with 3% dextrin or 1% whole soy flour. The results suggest that the treatments of medicinal herbs extracts, heat shock, and edible coating can be used as alternative for the use of chemical agents for the antibrowning of fresh-cut apples.

Furan Occurrence in Starchy Food Model Systems Processed at High Temperatures: Effect of Ascorbic Acid and Heating Conditions

Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation with the non-enzymatic browning in a wheat flour starchy food model system. Results showed that furan generation significantly increased in the presence of ascorbic acid after 7 min of heating (p < 0.05). The strongest effect was observed for baked products. Additionally, the furan content in fried products increased with the increase of the oil uptake levels. As for Maillard reactions, in general, the furan level in all samples linearly correlated with their degree of non-enzymatic browning, represented by L* and a* color parameters (e.g., wheat flour baked samples showed a R(2) of 0.88 and 0.87 for L* and a*, respectively), when the sample moisture content decreased during heating.

Optimization of Glycosylating Condition for Soy Protein Isolates and Maltodextrin by Maillard Reaction

The glycation of soy protein isolates and maltodextrin by Maillard wet-heating were evaluated. Glycosylating condition was optimized by the single factor test. The effects of temperature, heating time, protein content, weight ratio of maltodextrin to protein and dextrose equivalents (DE) of maltodextrins (Mds) on the degree of substitution (DS) and browning were investigated. The most optimum conditions are as follows: temperature 90°C, heating time 3h, the protein content 10mg/mL, the weight ratio 2, DE of maltodextrins 9~12. The degree of substitution and browning reaches 14.9% and 0.27 respectively. The aim of this work was to investigate the relationship between the conditions and the degree on the glycation of SPI and Mds.

Changes of quality of high hydrostatic pressure processed cloudy and clear strawberry juices during storage

Changes of quality of cloudy and clear strawberry juices processed by high hydrostatic pressure (HHP) at 600 MPa/4 min during 6-month storage at 4 and 25 °C were investigated. After 6 months of storage at 4 °C, ascorbic acid, anthocyanins and total phenols decreased by 39.41%, 29.76% and 16.22% in cloudy juices, and by 48.91%, 7.02% and 13.82% in clear juices, but the antioxidant capacity in both juices decreased by less than 10%. The decrease of these indices at 25 °C for 6 months almost doubled. The lightness (L⁎) and redness (a⁎) in both juices at 25 °C were significantly lower than at 4 °C, while total difference color (ΔE) and browning degree (BD) were significantly higher. 66.93% and 70.75% decreases of viscosity and 47.60% and 79.98% of cloud in cloudy juices were observed after 6 months of storage at 4 and 25 °C, respectively. The loss of ascorbic acid, anthocyanins, total phenols and antioxidant capacity fits well to a first-order equation. Total anthocyanin content was selected as a biomarker to predict the shelf life due to their influence on the consumer acceptance and higher sensitivity to the storage temperature. Strawberry juice is one of the popular fruit juices, and it requires strict processing treatment and storage conditions to protect its quality. HHP is one promising novel non-thermal technique and is likely to replace thermal processes. A better knowledge of effects of storage temperature on the quality of HHP-treated strawberry juice and its shelf life prediction through kinetics analysis of these changes is necessary. This study would provide technical support for commercial application of the HHP technique in strawberry juice processing.