EFFECT OF OSMOTIC TREATMENT WITH CONCENTRATED SUGAR AND SALT SOLUTIONS ON KINETICS AND COLOR IN VACUUM CONTACT DRYING

ABSTRACT

An experimental study of osmotic dehydration (OD) of selected heat‐sensitive products was carried out in a laboratory‐scale vacuum contact dryer. Cubes of potato and apple were examined as model heat‐sensitive objects. Experiments were conducted at different conduction heat input levels with wall temperatures in the range 35–45C under vacuum and also in pure vacuum without any external heat input. Detailed investigations were carried out of OD on drying performance, product temperature and color of the dried product.

PRACTICAL APPLICATIONS

Osmotic treatment of potato and apple samples using concentrated sugar solution shows better osmotic dehydration as well as drying rate in a vacuum contact drying system. This information may help to select the osmotic agent in any industrial application for faster drying rate in vacuum contact drying specially for food products. Moreover this work shows the analysis to find out the starting point of precipitation of osmotic agent inside the products in terms of drying time, temperature and moisture content. This information will be helpful for critical analysis in osmotic dehydration technique which in turns may help for optimum design.

     

INFLUENCE OF COMBINED MICROWAVE‐VACUUM DRYING ON DRYING KINETICS AND QUALITY OF DRIED TOMATO SLICES

ABSTRACT

The study investigated the influence of four microwave powers on the drying kinetics and quality of tomato slices in a microwave‐vacuum dryer at vacuum pressures of 0.04, 0.05 and 0.06 MPa. The results showed that increase in microwave‐vacuum drying conditions increased drying rates and resulted in decreased drying time from 84 to 14 min. The nonenzymatic browning index increased with microwave power whereas the overall flavor degradation was between 18.99 and 20.80%. The brightness and the yellowness of the dried tomatoes generally increased but there was a slight reduction in redness when compared with the fresh. The effective moisture diffusivity increased with microwave power and was 7.22 × 10^?9, 9.10 × 10^?9, 14.99 × 10^?9 and 25.19 × 10^?9 m²/s at respective microwave powers of 200, 300, 500 and 700 W.

PRACTICAL APPLICATIONS

Microwave‐vacuum drying is one of the advanced methods with numerous advantages including high thermal efficiency, shorter drying time and improved product quality. Tomato is the second most important vegetable with enormous health benefits, which include reduction of cholesterol, improvement of vision, maintenance of gut, lowering of hypertension, alleviation of diabetes, and prevention of urinary tract infections and gallstones. The quality of dried products obtained using the microwave‐vacuum dryer provides industries with method that can be used to enhance the quality of dried tomatoes. The dried product is a valuable ingredient in the preparation of soups and sauces, as well as in cosmetics and pharmaceutical formulations.

     

THIN-LAYER DRYING OF SPINACH LEAVES IN A CONVECTIVE DRYER

ABSTRACT

In the present work, spinach samples were dried using a pilot‐scale cabinet‐type convective dryer. Drying experiments were conducted using a constant air velocity of 1.2 m/s and four drying air temperatures of 50, 60, 70 and 80C. Drying rate increased with the increase in air temperature and thus reduced the drying time. The experimental drying data of spinach were applied to four moisture ratio models, namely, the Henderson and Pabis, Lewis, Page, and logarithmic models. Nonlinear regression analysis was performed to relate the parameters of the model with the drying conditions. The performance of these models is evaluated by comparing the coefficient of determination, R², and the reduced chi‐square,χ², between the observed and predicted moisture ratios. Among all the models, the logarithmic model was found to be the best for explaining the drying characteristics of spinach leaves. The effective moisture diffusivity varied from 6.590 × 10^?10to 1.927 × 10^?9 m²/s over the temperature range studied, with an activation energy of 34.35 kJ/mol for spinach leaves.

PRACTICAL APPLICATIONS

Drying, which is the oldest of food preservation practiced by humans, is the most important process to preserve agricultural products because it has a great effect on the quality of the dried products. The objective in drying foods is the reduction of the moisture content to a level that allows safe storage over an extended period. In this study, the drying kinetics of spinach leaves was studied in a convectional hot air dryer. The effect of air temperature on drying behaviors was determined. For the optimal products, the drying characteristics, namely, drying time and rehydration ratio, are considered. The dried spinach leaves could be used in the preparation of foods like puree, soups and baked products.

     

PRODUCTION, QUALITY ASSESSMENT AND ACCEPTABILITY OF AFRICAN YAM BEAN SPHENOSTYLIS STENOSCARPA SAUCE

ABSTRACT

Sauces (15 and 20% brine solution) were made from African yam beans (AYBs) using a combination of solid and liquid state fermentations as practiced in Indonesia. They were analyzed to ascertain their nutritive value, microbiological safety and consumer acceptability. Results showed that the protein, fat, ash and carbohydrate contents were 4.85, 3.82, 11.82 and 16.75%, respectively, for 15% brine solution sauce after spicing and concentration. The total microbial load (bacteria) of the sauces was relatively low (20.0 and 18.0 cfu/g × 10⁶) for the two concentrations of sauces, respectively. At 0.05 confidence level, the t‐tabulated value was greater than the t‐calculated value (2.09 > 0.01), showing that there was no significant difference between the general quality characteristics of the AYB sauce and the conventional soy sauce.

PRACTICAL APPLICATIONS

The product AYB sauce made from the solid state fermentation of African yam beans (an underutilized Nigerian legume) can be used as condiment in preparation of foods (gravies, soups, stews, jollof and fried rice, pastry fillings, etc.) at homes, restaurants and fast food companies. The commercial production of the sauce will help in the reduction of the pressure on soybeans, which is the major raw material for the production of soy sauce, and increase the utilization of the crop and income of the farmers of AYB.

     

"DELICIOUS PILAFA" APPLE DENSITY CHANGES AS A QUALITY INDEX OF MASS LOSS DEGRADATION DURING STORAGE

ABSTRACT

Since many years, the mass density of many agricultural products has been used as a quality‐sorting criterion, and automatic machines have been developed for that purpose. According to the literature, apple flesh density seems to be related to flesh stiffness, but this behavior is not common among all cultivars. However, there is a lack of information on the evolution of apple density during storage. This study aims to investigate changes of “Delicious Pilafa” apple density during storage. Fruits have been preserved at 0, 10 and 16C. Experiments have been repeated for three successive storage periods. Linear equations between density and mass loss have been developed for two ranges of storage temperatures, 0–10C and 10–16C. Moreover, an efficient multifactor linear equation that relates density to storage time and mass loss has also been calculated. “Delicious Pilafa” apples are characterized by a high mass loss rate during storage. Thus, the relationships developed in this study could be useful for quality assessment of stored fruits according to their mass loss.

PRACTICAL APPLICATIONS

Mass loss of “Delicious pilafa” apple during storage can be estimated via fruit density and storage time using the developed equations that refers to a variety of storage conditions. Fruit density can be easily measured as well as storage time can be accurately estimated at a certain moment of storage. Such mass loss correlation is important for “Delicious pilafa” apples, characterized from high mass loss rates during storage and thus this prediction procedure could be very useful as an objective quality criterion during storage. Equations that relate mass loss and storage time with fruit density could be also useful for the estimation of fruit's volume. This is particularly important for respiration rate measurements, where fruits volume is required. Using such relations the estimation of volume is feasible only with weighting and without immersing fruits in water that could affect respiration activity and favor spoilage development.

     

MODELING OF PREHEAT TREATMENT OPTIMIZATION APPLIED TO FRESH‐CUT “ROCHA” PEAR

ABSTRACT

Response surface methodology based on a five‐level, three‐variable central composite rotatable design was used for modeling the effects of preheat treatments on fresh‐cut “Rocha” pear quality. Studied variables were time (t: 0–150 min), temperature (T: 20–50C) and posttreatment storage time (St: 0–20 days, 5C). The quality‐affecting parameters including color, firmness, pH, soluble solid content, and total ascorbic acid content were the monitored dependent variables. Results provide reasonable estimation of the impact of preheat treatments on the quality of fresh‐cut “Rocha” pear and its shelf life. The time–temperature range of 33–41C during less than 20 min was selected as the conditions that best provided surface browning control, without impairing other studied quality parameters, with an estimated 8‐day shelf life period. The achieved kinetic changes of polyphenoloxidase, partial reduction in enzyme activity (ca. 23%) and depletion of phenolic content (ca. 11%) could be responsible for the browning control.

PRACTICAL APPLICATIONS

Minimal processing, namely cutting operations, triggers physiological reactions which limit fresh‐cut Rocha pear shelf life. Superficial browning is one of the major concerns to this industry, and new “clean” methodologies aiming at the inhibition of such reaction and maximization of the product shelf life will benefit not only from product marketability but also will respond to the consumers' demand of “chemical free” products. Heat treatments have been used to improve fresh‐cut commodities' browning resistance. The present work evaluated the use of preheat treatments against this physiological disorder during storage. Results will provide an optimized preheat treatment that grants high‐quality fresh‐cut Rocha pear with suitable shelf life.

     

DETERMINATION OF ORTHO-NASAL AROMA THRESHOLD FOR MULTICOLORED ASIAN LADY BEETLE IN A CONCORD GRAPE JUICE

ABSTRACT

Sensory evaluation was used to determine the aroma threshold of Harmonia axyridis (multicolored Asian lady beetle [MALB]) in Concord grape juice. Prior to Concord grape juice preparation, MALB was added to the Concord grapes at concentrations of 0 and 8.4 MALB/kg fresh grapes. To determine the odor threshold, the three alternative forced‐choice method of sample presentation was used, with an ascending concentration series of 0.5, 1.5 and 4.5 MALB/kg fresh grapes. The panel aroma threshold concentration, calculated using the best estimate threshold over two panel sessions, was 1.8 MALB/kg fresh grapes. Individual detection thresholds ranged from 0.29 to 7.79 MALB/kg fresh grapes, with 75% of the panelists having a detection threshold at or below 0.87 MALB/kg fresh grapes. These results indicate the influence of low numbers of MALB on Concord grape juice aroma, and suggest the importance of quality control programs, including the implementation of established tolerance limits, to monitor grape quality.

PRACTICAL APPLICATIONS

Harmonia axyridis, the multicolored Asian Ladybeetle (MALB), was originally introduced as a method of biocontrol. However, its presence is now becoming problematic with respect to crop quality. In order to minimize economic losses to the Concord grape industry, determination of the number of MALB required to produce a detectable change in Concord grape juice is critical for juice producers in the establishment of their quality control programs. Therefore, the objective of this study was to determine the aroma threshold level of MALB in Concord grape juice. The panel aroma threshold concentration, calculated using the best estimate threshold was 1.8 MALB/kg fresh grapes, with 75% of the panelists having a detection threshold at or below 0.87 MALB/kg fresh grapes. These results indicate the influence of low numbers of MALB on Concord grape juice aroma, and suggest the importance of quality control programs, including the implementation of established tolerance limits, to monitor grape quality.

     

INFLUENCE OF OSMOTIC DEHYDRATION ON THE VOLATILE PROFILE OF GUAVA FRUITS

ABSTRACT

The effect of osmotic dehydration (OD) on the volatile compounds of guava fruits was studied. Osmotic treatments were carried out at atmospheric pressure, at continuous vacuum and by applying a vacuum pulse (5 min under vacuum and the remaining time at atmospheric pressure) at different temperatures (30, 40 and 50C) and times (1, 2 and 3 h). The volatile compounds of fresh and dehydrated samples were obtained by simultaneous distillation–extraction, and were analyzed by gas chromatography/mass spectrometry. In general, OD caused changes in the concentration of volatiles, depending on the process conditions. The use of lower temperatures and shorter treatment times can diminish the loss of volatiles with respect to the fresh samples. The greatest damage to volatiles loss is produced at 50C for up to 2 h under both pulsed and continuous vacuum. The lowest total volatiles loss occurred at 30 and 40C for up to 3 h under pulsed vacuum or atmospheric pressure.

PRACTICAL APPLICATIONS

Consumer demand for high‐quality products with freshlike characteristics has promoted the development of a new category, minimally processed fruits and vegetables. Although these products present, as distinguishing features, simplicity in use and convenience, they generally perish more quickly than the original raw material because of tissue damage caused by mechanical operations. The use of osmotic dehydration process has been presented as a tool for the development of minimally processed fruits. The slight water activity reduction promoted by the process may provide stable products with good nutritional and sensorial quality and with characteristics similar to those of the fresh products. The application of minimal processing to tropical fruits can represent an interesting world market. Fruit flavor is an important quality factor that influences consumer acceptability, and for this reason, its study is relevant in the minimally processed food product.

     

TOTAL QUALITY INDEXES FOR EXTRA-VIRGIN OLIVE OILS

ABSTRACT

In this article, we propose a new and functional mathematical index, able to describe and compare the nutritional, safety and process quality in extra‐virgin olive oil, introducing a definition of “optimal” oil, through the use of appropriate distances in a N‐dimensional parameter space. Our index does not pretend to be the unique answer to the need of a “quality index,” but it presents a way through which we can establish if an extra‐virgin olive oil can be considered of high, medium or low quality. The main goal of our index is to link oil chemical quality to its commercial price; furthermore, it can be, in perspective, useful to detect the critical points (such as harvest time, drupe storage, processes and finally oil storage) during all the production chain, and to show how to increase nutritional, safety and technological quality.

PRACTICAL APPLICATIONS

The index could be mainly helpful for consumers because the only indication that they can use today, in order to operate a choice, is in general the price of the oil, which is not necessarily related to its quality. In fact, it is possible to relate our index to the oil price. This tool can also be addressed to producers, to help them to detect the critical points along the whole food production chain and eventually operate the needed corrections to obtain a high‐quality extra‐virgin olive oil, as stated in the Discussion.

     

THE BIOCHEMICAL AND SENSORY PROPERTIES OF GILTHEAD SEA BREAM (SPARUS AURATA) FROZEN AT DIFFERENT CHARACTERISTIC FREEZING TIMES

ABSTRACT

Skinned, vacuum‐packed, postrigor gilthead sea bream fillets were frozen individually with characteristic freezing times of 2, 18, 74 and 640 min (times to cool the thermal center of the fillets from ?1 to ?7C). Immediately after freezing, the fillets were thawed, and their quality was evaluated with tests related to muscle integrity, myofibrillar protein denaturation and aggregation, lipid degradation and changes in tenderness. The muscle integrity indices (activities of α‐glucosidase, β‐N‐acetyl‐glucosaminidase and (β‐hydroxy‐acyl‐coenzyme‐A dehydrogenase and the amount and protein content of centrifugal tissue fluids) showed that the freezing process itself clearly affected the integrity of muscles. Freezing of fillets with characteristic freezing time of 74 min caused more damage to muscles and hydrolysis of lipids than the other freezing times. Adenosine triphosphatase (ATP) ase activities and Ca²⁺ sensitivity of actomyosin extracts suggested that the freezing process itself, but not the freezing times, caused structural damage to myofibrillar proteins. No difference in the levels of salt‐soluble proteins and sulfhydryl contents in actomyosin extracts was found between the fresh and frozen fillets. Sensory evaluations showed that the cooked frozen fillets were less tender than the cooked fresh ones.

PRACTICAL APPLICATION

In commercial seafood industries, seafoods are frozen at a range of freezing times (rates) that depends mostly on the type of seafood, the type of freezer and freezer's operating conditions. Based on the work reported in the literature, freezing of seafoods at different freezing times may furnish favorable conditions for alterations in muscle structure, muscle proteins and lipids, and textural properties in general. These changes are related to alterations in quality of frozen seafoods and may affect their market. Therefore, knowledge of optimal conditions with respect to freezing rates for freezing commercially important seafoods, as farmed gilthead seabream is, is relevant to the seafood industry. This information can be obtained by experimental studies on changes in the chemical, biochemical, physical and sensory properties of seafoods frozen at different freezing times.

     

ACCELERATED STORAGE TESTING OF FREEZE-DRIED IMMOBILIZED LACTOBACILLUS ACIDOPHILUS-FERMENTED BANANA MEDIA

ABSTRACT

Freeze‐drying was applied as a drying method for the production of dehydrated immobilized Lactobacillus acidophilus‐fermented banana medium containing high levels of probiotics and appropriate prebiotic (mainly fructooligosaccharides) contents in an attempt to develop dried synbiotic products. Ca‐alginate and κ‐carrageenan were used for the immobilization of L. acidophilus, and the immobilized bacteria were employed directly in the banana media fermentation. The fermented products were then freeze‐dried. Results indicated that cell immobilization could provide effective protection to L. acidophilus, and reduce the damage caused by freezing and freeze‐drying. Meanwhile, accelerated storage testing using temperatures of 50, 60 and 70C was applied to the dehydrated products. Gel‐entrapped L. acidophilus appeared to have lower decimal reduction, and Ca‐alginate immobilized cells had a better survival than κ‐carrageenan. Results of accelerated storage test showed that immobilization could effectively increase the thermal resistance of entrapped microorganisms, and Ca‐alginate showed a better effect than κ‐carrageenan, and the beneficial effects increased with the decrease of the storage temperature. The freeze‐dried products exhibited little hygroscopicity because of the consumption of monosaccharides during fermentation. Results revealed that freeze‐drying could be used as a proper method for the development of dried product of immobilized L. acidophilus‐fermented banana media, and accelerated storage test could be used to evaluate the storage stability of the dried products.

PRACTICAL APPLICATIONS

This research demonstrates the feasibility of the application of accelerated storage testing to the prediction of shelf life and storage stability of freeze‐dried probiotic products manufactured by lactic acid bacteria fermentation. The Arrhenius equation was associated in this study. This will provide an efficient approach for the estimation of shelf life of probiotic products.

     

PHYSICAL–CHEMICAL AND SENSORY QUALITY EVALUATION OF GARLIC CULTIVARS

ABSTRACT

Physical–chemical quality of 14 garlic cultivars grown in Spain was analyzed, and the cultivars were classified into three types: purple, white and Chinese, in order to show the possible differences among them. The most useful instrumental color parameter to discriminate among the different types of garlic was lightness (L*). The high pH value of the purple‐type cultivar Moraluz, and the high content of d ‐glucose, d ‐fructose and total sugars of the Chinese‐type cultivars were quite remarkable. The consumer judges preferred the color and pungency of the purple‐type cultivar Morasol, while Chino Sprint stood out for its intense garlic odor. Finally, correlations between the physicochemical and the sensory parameters were studied. The red color intensity was correlated with lightness (L*) and with hue (h*); pH was correlated with chroma (C*) and moisture percentage was correlated with sucrose content.

PRACTICAL APPLICATIONS

One of the main objectives of this work was to advise growers on the selection of garlic seed. The data obtained in this work was sent to a regional research and advising agronomic center (Technical Agronomic Institute, provincial council of Albacete), where advice was given to local growers concerning the selection of the most adequate seeds, in terms of physical– chemical properties and consumer preference, plus agronomic performance (data not included in this article). The conclusions reached in this study will make an important contribution to the agronomic characterization of the garlic cultivars grown in Spain.

     

ANTIOXIDANT PROPERTIES OF LENTINUS EDODES AND AGARICUS BLAZEI EXTRACTS

ABSTRACT

This work aimed to evaluate the antioxidant activity of Lentinus edodes and Agaricus blazei mushrooms, as well as to measure the content of total phenolic compounds of mushroom extracts and verify the oxidative stability of soybean oil added with mushroom extracts that showed higher antioxidant activity according to the methods of the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^•) free radical scavenging and the β‐carotene/linoleic acid system. According to the DPPH^• method, the maximum antioxidant activity for L. edodes and A. blazei methanol extracts was 92.84 and 95.10%, respectively. For the β‐carotene/linoleic acid system, the highest values of antioxidant activity were 93.06% for L. edodes and 78.96% for A. blazei. The content of total phenolic compounds ranged from 7.21 to 128.44 and 26.67 to 134.67 mg gallic acid equivalent/g for L. edodes and A. blazei, respectively. The oxidative stability values provided by the Rancimat method indicated that the two varieties presented similar induction period of 19.85 h.

PRACTICAL APPLICATIONS

Mushrooms present high content of antioxidant compounds that are capable of reducing the harmful effects of free radicals. Among the antioxidants present in mushrooms, phenolic compounds stand out as phenolic acids, flavonoids and tocopherols. To decrease or prevent lipid oxidation, synthetic antioxidants are used as food additives. Nevertheless, studies have revealed that these compounds are likely to pose risks to human health. The concern regarding the safety of synthetic antioxidants has motivated the search of natural antioxidants that can substitute them totally or partially.

     

NONTHERMAL STERILIZATION OF GREEN COCONUT WATER FOR PACKAGING

ABSTRACT

A laboratory scale technique for nonthermal sterilization of green coconut water was developed. The process consisted of two‐stage filtrations under constant pressure using different filter media; namely, low ash filter paper (Whatman 42) in the first stage and cellulose nitrate membrane (0.2‐µm pore opening) in the second stage. The quality of the filtered water was evaluated with respect to microbial population, organoleptic characteristics, nutrient contents and physical properties. The water after the second stage of filtration was sterile with no visible growth of microbes on culture plates. The taste of the processed water did not change significantly; however, the flavor and overall acceptability decreased about 9 and 11%, respectively. The water also remained sterile after 1 month in aseptically packed condition, but overall acceptability further decreased by 6%. The filtration reduced different nutrients of the fresh water like fat, ash, total sugar, reducing sugar and protein by 40.0, 43.9, 23.4, 29.2 and 13.3%, respectively; the removal of K, Mg, Ca, Fe and Cu was 10.15, 16.14, 19.04, 20.85 and 22.21%, respectively. The removal of these nutrients increased surface tension and decreased viscosity of the coconut water.

PRACTICAL APPLICATIONS

Packaging of sterile green coconut water as soft drink has a good global market as it ensures its widespread availability, quantity and reasonable price. Non‐thermal sterilization by membrane filtration has been found to be an alternative to thermal sterilization as the later adversely deteriorates many essential qualities of this delicate coconut water. The present non‐thermal sterilization technique maintained the sterility, nutritional quality and desirable organoleptic profile of the processed water. Thus, this process could be applied for production of green coconut water as packaged soft drink.

     

COLOR QUALITY OF ROSE LIQUEUR

ABSTRACT

The effect of pretreatments and soaking conditions on the color quality of rose liqueur was investigated. Results show that (1) most of the anthocyanin in rose petals was dissolved within 48 h of soaking; (2) a longer soaking time led to a lower color quality due to browning ; (3) a base spirit at lower ethanol content extracted more anthocyanin and also resulted in more browning; (4) 50C air‐drying to 20% water content retained 90% of anthocyanins in rose petals; and (5) the soaking of dried petals in the base spirit yielded a product with less browning as compared with that of fresh petals. The process for making rose liqueur with the best color quality was found to be by soaking dried rose petals at a 1:10 ratio (rose petal : ethanol, w/w) in a base spirit containing 30–35% ethanol added with 0.6–0.8% citric acid for 24 h, then diluting the extract to 16% ethanol content.

PRACTICAL APPLICATIONS

This study provides an adequate process for the making of rose liqueur. Pre‐dehydration treatment can be applied on the raw material in the making of various anthocyanin‐containing beverages to improve the color quality. Findings in regard to the effect of ethanol concentration on anthocyanin extraction and the color stability of the product can also be valuable references to wine industry.

     

ANALYSIS OF TEXTURE OF BONELESS, FULLY FRIED BREADED CHICKEN PATTIES AS AFFECTED BY PROCESSING FACTORS

ABSTRACT

Battered and breaded, fully cooked, boneless chicken patties were analyzed based on processing variables (substrate, breading, rethermalization method, shape) and six objective texture attributes. Analysis of variance compared both individual samples and main effects, while statistical cluster analysis classified products based on their independent characteristics and the objective texture attributes. One sample (baked, crackermeal, all meat, nuggets) was significantly higher in most textural attributes. The soy‐containing samples were texturally similar. Breading and shape were not significantly different for the main effects of crust fracture force and work. Samples were sorted into clusters: cluster 1 characterized by oat bran breading, cluster 2 by crackermeal breading and soy‐containing substrate, cluster 3 by crackermeal and all‐meat substrate, and cluster 4 by Japanese bread crumbs and patty shape. Statistically classifying breaded chicken patties could lead to the development of a reliable, statistically based and easy‐to‐implement process that would aid quality control and product development in the meat industry.

PRACTICAL APPLICATIONS

Characterization of the textural attributes of breaded meat patties such that differentiation could be achieved with a common instrument (texture analyzer) could provide a reliable and easy‐to‐implement method to assess the quality of texture in meat products that would be beneficial to the meat industry for both quality control and product development purposes.

     

DEVELOPMENT OF A BLENDED NONALCOHOLIC BEVERAGE COMPOSED OF COCONUT WATER AND CASHEW APPLE JUICE CONTAINING CAFFEINE

ABSTRACT

In this work, the stability of a blended beverage composed by coconut water and clarified cashew apple juice (“cajuina”) is presented. The physicochemical, microbiological and sensory stability of a blended nonalcoholic beverage composed of coconut water and cajuina (80:20 v/v) were evaluated during 6 months. The results showed that the beverage presented good stability in all analyzed parameters except for vitamin C, which presented a loss of about 80% of the initial content. The beverage color also presented changes during the storage time. Despite these alterations, the product acceptance during the storage period did not show any rejection.

PRACTICAL APPLICATIONS

The development of blended beverages is a good way of improving the nutritional quality of traditional products. By mixing two or more kinds of fruits, a product with more vitamins and minerals and with different sensory and flavor characteristics when compared to the raw materials is obtained. In the present work, coconut water and cashew apple juice were mixed to obtain a different product combining the nutritional components from both fruits. The blended beverage combines the high vitamin C content of the cashew apple juice with the high mineral level of the coconut water. Caffeine was also added conferring stimulating properties to the product. The product acceptance was evaluated by sensory analysis and presented good acceptance until 6 months of storage at room temperature, presenting the required characteristics for a commercial product.

     

ROLE OF CARROT ON SHELF STABILITY OF DAIRY DESSERT (RASOGOLLA) DURING REFRIGERATED STORAGE

ABSTRACT

Carotene‐enriched carrots (Daucus carota L. var. Chantenay) were evaluated for their inhibitory effects on acidity development and lipid oxidation in rasogolla during refrigerated storage. Rasogolla is mashed fresh cheese or cottage cheese boiled in rounded shape in concentrated sugar syrup. Six types of rasogolla samples containing carrot paste at 0, 10, 20, 30, 40 and 50% were prepared and stored in closed container at refrigerated condition for 20 days. Chemical changes were measured for acidity of syrup, pH of syrup, free fatty acid content and absorptivity of rasogolla samples, and sensory evaluation of rasogolla samples at days 0, 5, 10, 15 and 20 of storage. The carrot pastes showed significant protection against lipid oxidation, acidity development and sensory quality maintenance in rasogolla. Higher levels of carrot pastes were more effective to increase shelf stability in rasogolla at different tested storage times. However, after day 10 of storage, carrot concentration showed negative result, i.e., enhancement of rate of lipid oxidation of rasogolla samples and its syrups along with visual color destruction. Also, excess quantity of carrot in rasogolla reduces the overall acceptance by the consumer. According to the overall result of shelf stability, it could be suggested that carrot concentration up to 30% should be used in rasogolla for long duration of storage, i.e., above 10 days.

PRACTICAL APPLICATIONS

Traditional dairy products such as Rasogolla are important, well balanced food, which contribute a number of nutrients in relation to our need for good nutrition and health. Rasogollas' projected demand is 6000 tonnes in 2009 ( Karunanithy et al. 2007 ). Carrot is a good source of carotene specially beta‐carotene and serve as a good source of natural antioxidant. Fortification of carrot in dairy product serves as functional or health food for people of all age group. It also imparts a safe and attractive color to the dairy product. Besides, it is also cost effective for the dairy industry, because carrot is much cheaper than milk or channa (a dairy product analogous to cottage cheese). Study on the role of carrot on shelf stability of rasogolla under refrigerated storage is an attempt to establish this new product in the dairy industry.

     

Effect of substituting fresh‐cut perennial ryegrass with fresh‐cut white clover on bovine milk fatty acid profile

BACKGROUND

Including forage legumes in dairy systems can help address increasing environmental/economic concerns about perennial ryegrass monoculture pastures. This work investigated the effect of substituting fresh‐cut grass with increasing quantities of fresh‐cut white clover (WC) on milk fatty acid (FA) profile and transfer efficiency of dietary linoleic (LA) and α‐linolenic (ALNA) acids to milk fat. Three groups of three crossbred dairy cows were used in a 3 × 3 crossover design. Dietary treatments were 0 g kg^?1 WC + 600 g kg^?1 grass, 200 g kg^?1 WC + 400 g kg^?1 grass, and 400 g kg^?1 WC + 200 g kg^?1 grass. All treatments were supplemented with 400 g kg^?1 concentrates on a dry matter basis. Cows had a 19‐day adaptation period to the experimental diet before a 6‐day measurement period in individual tie stalls.

RESULTS

Increasing dietary WC did not affect dry matter intake, milk yield or milk concentrations of fat, protein or lactose. Milk polyunsaturated FA concentrations (total n‐3, total n‐6, LA and ALNA) and transfer efficiency of LA and ALNA were increased with increasing dietary WC supply.

CONCLUSION

Inclusion of WC in pastures may increase concentrations of nutritionally beneficial FA, without influencing milk yield and basic composition, but any implications on human health cannot be drawn. © 2018 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

     

EFFECT OF CHITOSAN COATING ON SHELF LIFE AND QUALITY OF FRESH-CUT MUSHROOM

ABSTRACT

The effect of chitosan coating in fresh‐cut mushroom preservation, including microbiological, enzyme activities, color characteristics and chemical quality attributes, was examined. However, application of chitosan coating to enzyme activity control and quality maintenance of fresh‐cut mushroom was investigated. Fresh‐cut mushrooms were treated with aqueous solution of 0.5, 1 and 2 g chitosan/100 mL, placed in polyethylene bags, and then stored at 4C. Application of chitosan coating delayed discoloration associated with reduced enzyme activities of polyphenoloxidase, peroxidase, catalase, phenylalanine ammonia lyase and laccase, as well as lower total phenolic content. Also, it reduced enzyme activities of cellulase, total amylase and α‐amylase. Microbiological development of the fresh‐cut mushroom treated with chitosan coating was also inhibited compared to the control. The results showed that increasing the concentration of chitosan coating enhanced the beneficial effects of chitosan on extended shelf life and maintained quality of fresh‐cut mushroom.

PRACTICAL APPLICATIONS

In general, the results showed that the application of chitosan coating (with optimum concentration of 2%) of oyster mushroom was observed to greatly inhibit the enzyme activities and lowest microbial count (Y, M and B) during storage at 4C for 15 days. Recommendations for selection of an appropriate chitosan concentration with refrigeration at 4C were given to be a potentially useful tool for extending the shelf life of fresh oyster mushroom. Furthermore, from a technological point of view, it would be conceivable to use chitosan coating in processed mushrooms provided that their safety is assessed and their commercial feasibility is demonstrated. It is concluded that the technique used produced good results; the product showed good quality during processing and storage with respect to microbiological, physical and chemical properties. Also, this technique is important to prevent the decrease in market value and the concomitant economic losses.