Microstructure and rheology of apple jam as influenced by cross-linked acetylated starch

Sugar and no sugar added fruit microalgae-enriched jams: a study about their physicochemical, rheological, and textural properties

Jams are preparations of fruits whose main preserving agent is sugar. Due to this, health concerns of consumers have resulted in a sugar reduction, and its replacement using alternative sweeteners and introducing new ingredients enhancing nutritional properties. In this study, four types of fruits jams (plum, strawberry, apple, and peach), with or without sugar, were prepared using two microalgae biomass, Arthrospira platensis (Spirulina) and Chlorella vulgaris, and Dunaliella salina extract as ingredients at different mix levels of concentrations, 0.10%–0.10%–0.05% respectively, for plum; 0.04%–0.00%–0.01 respectively, for strawberry; 0.06%–0.04%–0.00% respectively, for apple and 0.00%–0.01%–0.04% respectively, for peach. Physicochemical, rheological, and textural parameters were evaluated. Substitution of sugar/fructose syrup in the jam’s preparation caused changes in pH values, solid soluble content, and rheological and textural properties compared to sugar jams. Using sugar or sweeteners as isomalt, stevia and sucralose and microalgae biomass or extract showed significant changes in colour coordinates, however, these differences were not perceptible by the human eye. Jams containing microalgae biomass-extract showed higher G', G'', G*, and η* values than their corresponding control samples. All the jams presented weak-gel characteristics, distinguishing fruit jams. However, the results of weak-gel model analysis suggest that the influence of the different ingredients in the food system depends not only on their concentration but also on the interactions in the gel structure. Strawberry and apple jams showed no significant differences between microalgae biomass-extract samples and control samples, for both sugar and no sugar added jams being the best-obtained samples.

Food Hydrocolloids from Butternut Squash (Cucurbita moschata) Peel: Rheological Properties and Their Use in Carica papaya Jam

Hydrocolloids are a class of functional ingredients that are widely used in the development of food structures. The hydrocolloids are mainly polysaccharides and some proteins that are applied in various food products. For this reason, natural sources that are friendly to the environment must be sought for their extraction. Therefore, this study aimed to extract hydrocolloids from butternut squash (Cucurbita moschata) peels-HBSP-and determine the proximal composition and rheological properties as well as their use effect in a microstructure product like fruit jam from Carica papaya. Hydrocolloids were obtained from butternut squash at pH 3, 7, and 10 and at different temperatures, presenting higher yield values at 80 °C with higher carbohydrate and protein contents and non-Newtonian flow behavior type shear-thinning. In order to analyze the influence of HBSP on the rheological properties of the microstructured product, the samples were employed as a partial substitute of pectin in C. papaya jam (CPJ), showing a positive effect on the jam matrix due to the addition of hydrocolloids. The physicochemical properties of jams did not present significant differences. CPJ presents non-Newtonian behavior type shear-thinning adjusting to the Herschel-Bulkley model. The dynamic viscoelastic rheological test characterized the jam as a gel-like state when the storage modulus values were higher than the loss modulus values in the frequency ranges studied. Regarding the addition of HBSP, this modified the color parameter, presenting a reddish color with an increase in tonality, and the sensory evaluation showed that the M3 sample was better than the other products, with a higher level of satisfaction. The obtained results show that butternut squash peel is suitable for the obtention of hydrocolloids, and they can be used as a raw material in the development and formulation of food products, as well as their byproducts can be used to solve problems with organic waste from the agroindustry in an environmentally friendly way.