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Fruit powder
The document discusses the health benefits of fruit powders and their growing popularity as alternatives to sugary beverages, emphasizing their nutritional value including dietary fiber, vitamins, and antioxidants. It outlines methods for production, particularly focusing on different drying techniques such as spray drying and drum drying, and highlights factors that affect powder properties like moisture content and bulk density. Additionally, it addresses challenges in drying fruit juices due to their hygroscopic and thermoplastic properties, suggesting the use of carrier agents like maltodextrin to enhance stability and reduce stickiness.
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Fruit powder
- 1. Fruit Powders PREETI BIRWAL PH.D(DE) ICAR-NDRI
- 2. Introduction The popularityof fruits may be attributed to consumer perception of their health benefits. In the case of fruit juices, many consumers are now looking for healthy alternatives to the traditional carbonated beverages. Fruits are rich in dietary fibre as well as phytonutrients, especially antioxidants, and have no cholesterol. The availability in the market of natural fruit juices derived from fresh fruits is a welcome alternative Fruits are important sources of vitamins and carbohydrates. They are naturally sweet and low in calories. Different fruits contain different type of vitamins, so it is important to have a variety of fruits. Fruits are the important intake of our daily diet life. There is no cause of side effect by fruits because it provides necessary vitamins to our body. The vitamins are important to humans for providing energy to away from various kinds of sickness
- 3. Fruit Powder The powdercan be used as an ingredient for cooking food or as a flavoring agent in some products. Its advantages consist of (a) a long shelf life at ambient temperature due to low water activity, (b) low logistic expenditures due to little weight and volume, and (c) vast multi disciplinary uses.
- 4. One of thewidely spread methods of preserving such products consists in drying both fruits and berries as well as organization of production of various kinds of the new products in a form of powders either from juices and extracts ( totally soluble) or powders obtained from whole fruits including cellular tissue and other components of fruits which undergo processing to two directions are: I- production of soluble fruit-dairy powders by spray drying; 2- production of fruit and vegetable powders by convective drying.
- 5. The dryingof pure (without any additives) juices from fruits is quite Complex. It is determined primarily by the thermoplastic properties of the drying material as well as the considerably hygroscopic nature of the powder-like product. Chemical composition of juices is very complex too, approx. 90% of dry substances in juices and purees made up of hydrocarbons: monosaccharides (glucose, fructose), disaccharides (saccharose) and polysaccharides. To the nutrient substances are added hydrocarbons, nitrogen containing substances, organic acids, plyphenol substances, vitamins etc. Under the influence of temperature and air oxygen inside the spray drying chamber various complicated transformations of component substances may take place which reveal themselves in changing of color and decrease of the nutrient quality.
- 6. Steps Sorting Grading Cleaning Sulphating Alkaline dip Blanking Juice extraction Clarification Filtration Juice concentration Drying
- 9. Drying Drum Drying Spray Drying Freeze Drying Microwave and dielectric Drying Spouted Bed Drying Pneumatic and Flash Drying Superheated Steam Drying Fluidization Bed drying Foam Drying Rotary Belt and Tunnel Drying
- 10. Fruits and Vegetables Fruit puree( Grapes, apple, cherry) Grape juice Lime juice Pear juice Pineapple juice Mango juice Orange juice Citrus juices Blueberry juice Beetroot juice Carrot juice Passion fruit juice Acerola juice Coconut juice Other vegetable juices
- 12. Dryer Selection Chart Aguide to dyer selection
- 13. FORMULATION ANDEVALUATION OF A POWDER Production of powder by drum dryer using maltodextrin and Arabic gum as adjuncts MD were preferred in facet of appearance, color, and overall liking, while those with AG were favored in their aroma and taste. Micro-encapsulated powders Sugar-rich products Fruit powder is just one step past drying fruit, too; after a brief conditioning phase, all you have to do is pulverize it. For best color, taste and texture, use the freshest, ripest fruit available.
- 14. Powder characteristics Bulkdensity Particle morphology Angle of repose Wettability Dispersion Solubility Moisture content Free flowing Fine Dustless Granules Agglomerated Lumps Hygroscopic Hydrophobic Thermoplastic
- 16. A typical two- stage spray dryer Source: DairyProcessing Handbook. Published by Tetra Pak Processing Systems AB, S-221 86 Lund, Sweden. pg. 369.
- 17. Operating conditions Electricityheater heated inlet air until 80-200°C. when outlet air temperature was in the range of 100-110°C. Rotary atomizer with 25000-rpm speed. Cyclone with effective diameter 10 cm separated the air-powder mix. The ambient air ambient temperature is about 20-25°C and relative humidity of 35-45%. 0.5-0.8 g cm3 density.
- 18. Source: Dairy Processing Handbook. Published byTetra Pak Processing Systems AB, S-221 86 Lund, Sweden. pg. 370. FILTERM AT DRYER
- 19. Factors Affecting PowderProperties Inlet temperature Powder properties such as moisture content, bulk density, particle size, hygroscopicity and morphology were affected by inlet temperature. It was found that at a constant feed flow rate, increasing the inlet air temperature reduced the residual moisture content. Increased temperature caused the reduction in bulk density. An increase in the inlet air temperature often results in a rapid formation of dried layer on the droplet surface and particle size and it causes the skinning over or casehardening on the droplets at the higher temperatures. This leads to the formation of vapor-impermeable films on the droplet surface, followed by the formation of vapor bubbles and, consequently the droplet expansion increase of drying air temperature generally causes the decrease in bulk, particle density and provides the greater tendency to the particles to hollow
- 20. higher inletair temperature leads to the production of larger particles and causes the higher swelling. The higher drying temperature is lower the moisture content and increase its hygroscopicity (its capacity to absorb ambient moisture). This is related to the water concentration gradient between the product and the surrounding air, which is great for the less moist powder. On the other hand, the increase of inlet air temperature has reduced the yield and it might be caused by melting of the powder and cohesion wall and therefore the amount of powder production and yield was reduced When the inlet air temperature was low, the particles showed a shriveled surface, while increasing drying temperatures resulted in a larger number of particles with smooth surface.
- 21. Air flow rate The increased residence time led to the greater degree of moisture removal. As a result, an increase of the drying air flow rate, decrease the residence time of the product in the drying chamber and it leads to have higher moisture contents. In addition, the effect of drying air flow rate of powder bulk density depends on its effect on moisture content due to the sticky nature of the product.
- 22. Atomizer speed Theresidual moisture content was decreased when increasing the atomizer speed. At higher atomizer speed, the smaller droplets were produced and more moisture was evaporated resulting from an increased contact surface.
- 23. Feed flow rates Higher flow rates imply in a shorter contact time between the feed and drying air and making the heat transfer less efficient and thus caused the lower water evaporation. The higher feed flow rate showed a negative effect on process yield and that was resulting the decreased heat, mass transfer and the lower process yield. In addition, when higher feed rates were used, a dripping inside the main chamber was observed, when the mixture was passed straight to the chamber and that was not atomized and finally resulting the lower process yield.
- 25. Type of carrieragent The result showed that the higher the maltodextrin dextrose equivalent (DE) causes higher the moisture content in the powder. This probably due to the chemical structure of high-DE maltodextrins, which have a high number of ramifications with hydrophilic groups, and thus can easily bind to water molecules from the ambient air during powder handling after the spray drying. Additionally, higher maltodextrin DE caused the increase in bulk density in the powder due to its stickiness. The higher maltodextrin DE was produced the lower glass transition temperature and it lower the elevation of the Tg in fruit pulp- maltodextrin mixture
- 26. The resultwas revealed that the particles produced with maltodextrin 10DE showed the lowest moisture adsorption rate, while the samples were produced with maltodextrin 20DE and gum Arabic had more hygroscopic and with faster water adsorption and the lower moisture in the powders The different type of carrier agent was having the variance in powder solubility
- 27. Problems Some researchersclaimed that drying of fruit juice could produce the fruit powder that reconstituted rapidly to a fine product resembling the original juice. Nonetheless, there are some difficulties in drying the fruit juice with high sugar content due to their thermoplasticity and hygroscopicity at high temperatues and humidity levels causing their packaging and utilization in trouble These characteristics are attributed to low molecular weight sugars such as fructose, glucose and sucrose and organic acids such as citric, malic and tartaric that are the major solids in fruit juices The low glass transition temperature (Tg), high hydroscopy, low melting point, and high water solubility of these solids lead to highly sticky or rubbery product when dried
- 28. Natural hygroscopicand thermoplastic property physical properties of fruit juice aided to drying. These of fruit juice is the basis problem in transport and agent materials include corn syrup; natural gums, sucrose, handling of fruit juice powder produced in spray malt dextrin etc…caused powder production and prevent dryer agent materials include corn syrup; natural gums, sucrose, malt dextrin
- 29. The drum dryingparameters such as drying temperature, Feed rate, rotation speed, feed concentration, and surrounding air condition are influential to the attributes of drum-dried food such as particle size, bulk density, moisture content, and solubility
- 30. Stickiness issues duringspray drying • Stickiness on the drier wall (spray drying) • Wet and plastic appearance • Agglomeration and clumping in packing container • Operational problems • Losses
- 31.
- 32. Products exhibiting stickinessduring drying • Products with high amount of sugars or organic acids – Fruit juices/pieces/purees/leathers – Honey – Molasses – Whey (acid or sweet) – High DE maltodextrins (DE>30) – Pure sugars- glucose, sucrose, fructose – High acid foods • High fat foods
- 33. Major factors causingstickiness • High hygroscopicity • High solubility • Low melting point temperature • Low glass transition temperature (related to thermoplasticity)
- 34. What is aglass transition? – Amorphous • non-aligned molecular structure • very hygroscopic • go through glass transition • predominant in dried food – Crystalline • aligned molecular structure • non hygroscopic • no glass transition Physical states of dried solid materials
- 35. Semi-crystalline solid Liquidsolution Grinding Extrusion cooking Thermal melting & cooling Rapid water removal- drying Rapid cooling below Tg water <-135oC honey <-45oC Amorphous solid (glass) Crystalline solid
- 36. Solid Liquid Glass transition Stickiness Propertyof an amorphous solid
- 37. _______________________________________________________ Food materials Tg(o C)abc _______________________________________________________ Fructose 14 Glucose 31 Galactose 32 Sucrose 62 Maltose 87 Lactose 101 Citric acid 6 Tartaric acid 18 Malic acid -21 Lactic acid -60 Maltodextrins DEd 36 (MW=550) 100 DE 25 (MW=720) 121 DE 20 (MW=900) 141 DE 10 (MW=1800) 160 DE 5 (MW=3600) 188 Starch 243e Ice-cream f -34.3 Honeyg -42 to -51 Glass transition temperature of various food materials
- 38. Spray drying ofsticky product some guideline • Drying below the glass transition temperature (often not feasible) • Mild drying temperature conditions • Increasing the Tg by adding high molecular weight materials (such as maltodextrins)- a predictive approach needed according to the composition • Immediate cooling of the product below its Tg • Appropriate drier design to suit the sticky product
- 39. The thermoplasticityand hygroscopicity troubles occurring in drying the fruit juice with high sugar content can be overcome by adding some drying carriers such as maltodextrin (MD) and Arabic gum (AG). These drying adjuncts are high molecular weight compounds that have high Tg , accordingly, they can raise the Tg Value of feed and the subsequent powder. MD is the most popular in spray drying due to its physical properties such as high water solubility; while, AG is recommended For fruit juice drying due to its emulsification properties and ease of dissolution in water. MD consists of b-D-glucose units linked mainly by glycosidic bonds and are typically classified by their dextrose equivalent (DE). MD could improve the stability of fruit powder with high sugar content because it reduced the stickiness and agglomeration problems during storage.
- 40. Dust Prevention Dust generationcan lead to a number of problems for food powders. These can be summarised as follows: (i) Health problems, in particular allergy problems; (ii) (ii) contamination and plant hygiene issues due to dust settling and sticking onto equipment; and (iii) fire/explosion hazards. (iii) Sensors for measuring carbon-monoxide have been developed and are already industrially implemented in the dairy industry
- 41. Changes during Storage Loss of vitamins Loss of natural pigments Browning reaction and rill of sulphrous groups Oxidative degradation and flavor loss Texture and reconstitute ability Glass transition point Microbiological hazard