Physicochemical, Functional and Antioxidant Properties of Tropical Fruits Co-products.

The aim of this study was to determine the physicochemical, functional and antioxidant properties of mango (MAC), pineapple (PAC) and passion fruit (PFC) co-products in order to evaluate them as ingredients for food application. Proximate composition showed low fat content (0.95-5.64 g/100 g), and high levels of dietary fiber. In pineapple and passion fruit co-products, dietary fiber represented more than 50 % of the sample. Low pH, water activity, along with high acidity indicated that these co-products would not be easily susceptible to deterioration as food ingredients. Pineapple and passion fruit co-products had significant (p < 0.05) water holding capacity (4.96 and 4.31 g water/g sample, respectively), however oil holding capacity was low (1.59-1.85 g oil/g sample) for the three matrices studied. Regarding the phenolic content, values ranged from 3.78 to 4.67 mg gallic acid equivalent/g, with MAC showing the highest content. Through high performance liquid chromatography analysis, six compounds were identified and quantified (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, epicatechin, and mangiferin) in the fruit co-products. As observed for the phenolic content, the highest antioxidant activity (p < 0.05) was found in MAC when measured by both DPPH and ABTS methods. The results indicated that the fruit co-products under evaluation could be used as functional ingredient to provide dietary fiber and natural antioxidants to food products.

Characterisation and potential application of pineapple pomace in an extruded product for fibre enhancement.

This study characterised pineapple pomace (PP) and evaluated its application in extrusion to enhance fibre content of the final product. The pomace had low fat (0.61%) and high dietary fibre (45.22%), showing its potential for fibre enrichment of nutritionally poor products, as some extruded snacks. Results also showed low microbiological counts, water activity, and pH indicating good microbiological quality and low risk of physicochemical deterioration. During extrusion, pomace (0%, 10.5% and 21%), moisture (14%, 15% and 16%) and temperature (140 and 160°C) were evaluated. The PP addition decreased expansion and luminosity; while increasing redness of the extrudates compared to the control (0% pomace/14% moisture/140°C). When hardness, yellowness, water absorption, and bulk density were compared to the control, there was no effect (p>0.05) of 10.5% PP addition on the extrudates, indicating that, at this level, PP could be added without affecting the properties of the final extruded product.

Physicochemical and thermal properties of Phaseolus vulgaris L. var. Great Northern bean starch.

UNLABELLED: The compositions and properties of 5 Great Northern bean cultivars (Beryl-R, Coyne, Gemini, Marquis, and Orion) were investigated. Starch was isolated from each cultivar by a wet milling process. Isolated, unmodified starches were characterized for granular, molecular, thermal, and rheological properties. Smooth surfaces and essentially similar granule sizes and shapes were observed among all cultivars. Amylose contents were in the range 21.0% to 22.6%. Amylose and amylopectin molecular weights were approximately 10(5) and 10(9) Da, respectively. Typical C-type X-ray pattern was observed in all cultivars. Significant differences were observed among cultivars in percentage relative crystallinities, which were in the range 18.2% to 23.8%. The relative crystallinity was independent of amylose proportion and molecular weight. The 5 Great Northern bean cultivars differed in their thermal and rheological properties. Coyne and Gemini had low gelatinization enthalpies. In pasting profile analysis, Coyne had the lowest peak and final viscosities. Granule size, polymer proportion, and molecular weights had major influences on gelatinization and pasting properties of Great Northern bean starches. PRACTICAL APPLICATION: Great Northern bean is one of the major varieties of dry-edible beans produced worldwide. Starch is the major component in Great Northern beans, which accounts for approximately 40% of its composition. Although most legume starches have been studied in detail, physicochemical and functional properties of Great Northern bean starch are largely unknown. This study investigated the properties and thermal behaviors of 5 Great Northern bean cultivars. The new information reported in this article, on starch properties, would pave ways to find new ingredient and product applications for Great Northern beans in food processing.

Starch gelatinization.

Starch occurs as highly organized structures, known as starch granules. Starch has unique thermal properties and functionality that have permitted its wide use in food products and industrial applications. When heated in water, starch undergoes a transition process, during which the granules break down into a mixture of polymers-in-solution, known as gelatinization. The sequence of structural transformations that the starch granule undergoes during this order-to-disorder transition has been extensively researched. None of the published starch gelatinization theories can fully and adequately explain the exact mechanism of sequential structural changes that starch granules undergo during gelatinization. This chapter analyzes several published theories and summarizes our current understanding of the starch gelatinization process.

Gelatinization and solubility of corn starch during heating in excess water: new insights.

Starch gelatinization is associated with the disruption of granular structure causing starch molecules to disperse in water. This study was designed to examine starch granules as they were heated in water, and their resulting morphological, structural, and solubility traits. The results indicate that starch gelatinization is a more complex process than the previously suggested order-to-disorder transition. The energy absorbed by the granules facilitates the rearrangement or formation of new bonds among molecules prior to the temperatures normally associated with the melting of amylopectin crystallites during gelatinization. It is also evident that amylose plays an important role during the initial stages of corn starch gelatinization.