Spray-Drying of Green or Gold Kiwifruit Juice–Milk Mixtures; Novel Formulations and Processes to Retain Natural Fruit Colour and Antioxidants

Abstract

This study describes novel formulations and approaches to produce reconstitutable (in water) spray dried kiwifruit milk powders that possess the intrinsic fruit colour and antioxidants of kiwifruits. Novel feed formulations, containing the aqueous fraction of green or gold kiwifruit puree, skim milk, fortifying zinc (in the form of zinc citrate) and a minimal amount of maltodextrin (3 % w/w), were spray dried at a relatively low inlet temperature (150°C) to produce kiwifruit juice-milk powders with good dissolution efficiency (complete dissolution in 21-28 s), low water activity (0.22-0.28) and high retention of vitamin C, phenolics and carotenoid antioxidants. Both the green and gold kiwifruit juice-milk powders were pseudoplastic-like materials. Their reconstituted aqueous solutions had viscosity of 2-23 mPa·s and exhibited a shear rate dependence. Adding kiwifruit pulp residue to the feed solution at a mass ratio of 25:75 significantly enhanced the dissolution efficiency and the natural kiwifruit colour of the product powders without affecting the total phenolic and vitamin C contents. Preheating the feed solution to 50°C for 1 min had a positive impact on the physicochemical attributes and bioactive profile of kiwifruit juice-milk powders, including a greater retention of initial kiwifruit juice colour, lower water activity, better dissolution efficiency and a higher total phenolic content. The powders obtained in this study contain multiple health-promoting nutrients and bioactives including kiwifruit antioxidants and milk proteins, and can be used in beverages or as functional ingredients for nutraceutical applications.

Spray‐Drying of Milk–Blackberry Pulp Mixture: Effect of Carrier Agent on the Physical Properties of Powder, Water Sorption, and Glass Transition Temperature

“…These differences may be related to environmental exposure of the powder surface during handling and storage of the product. Low values of water activity were also observed by Sun‐Waterhouse and Waterhouse () for spray‐dried kiwi juice‐milk mixtures. The results showed values of powder water activities between 0.22 and 0.28 and a high retention of vitamin C, carotenoids and phenolics.…”

“…The hygroscopicity ( H ) was analyzed by spreading 1 g of powder uniformly on plastic dishes and placing these dishes in a desiccator at relative humidity of 75 ± 1% and 20 °C over a saturated solution of NaCl for a period of time of 7 days (Sun‐Waterhouse & Waterhouse, ). Hygroscopicity was evaluated using the final powder weight, Eq.…”

Fourier Transform Infrared and Raman and Hyperspectral Imaging Techniques for Quality Determinations of Powdery Foods: A Review

“…Almost all dry powders have longer shelf‐life, and lower transportation and storage costs than conventional foods. Nevertheless, more attentions should be drawn toward quality evaluations of food stuff particles in such parameters as chemical composition (regarding starch, protein) (Soukoulis and others ; Sun‐Waterhouse and Waterhouse ), adulteration (such as species, origin) (Zheng and He ), mycotoxin content (regarding aflatoxin) (Teena and others ), and parasitic infection (as might be red flour beetles or weevils) (Campbell and Arbogast ), as shown in Figure . The chemical composition in a food product is the basis for determining its nutritional value and its overall acceptance, because this composition is what makes food powders different from each other, and generate desired products (Carneiro and others ).…”

Water properties in pâtés enriched with potato juice

“…The fact that such enrichment alternates the physicochemical and sensory properties of the base product must be taken into account [15][16][17]. As previously determined, the form in which potato juice is applied has influence on product quality [18][19][20][21].…”