scholarly journals Modification of Apple Pomace by Extrusion Processing: Studies on the Composition, Polymer Structures, and Functional Properties

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1385
Author(s):  
Vera Schmid ◽  
Antje Trabert ◽  
Judith Schäfer ◽  
Mirko Bunzel ◽  
Heike P. Karbstein ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Dietary Fiber ◽  
Functional Properties ◽  
Apple Pomace ◽  
Raw Material ◽  
Size Analysis ◽  
Extrusion Processing ◽  
Structural And Functional Properties ◽  
Pore Size Analysis ◽  
By Products

By-products of fruit and vegetable processing are an inexpensive and sustainable source of dietary fiber, potentially offering valuable functional properties such as water binding and thickening. Due to these favorable properties, they can be utilized to reformulate widely-consumed foods, e.g., bakery products or beverages. In this study, apple pomace was used as a model system to study whether extrusion technology affects food by-product functionality and thus has the potential to broaden the application of by-products in foods. The effect of the process parameters and the extent of thermo-mechanical treatment on the structural and functional properties of apple pomace were analyzed after extrusion trials using various screw speeds, water contents, and barrel temperatures. Compared to the raw material, apple pomace extruded at Tbarrel = 100 °C, n = 700 min−1 and mH2O = 17% showed an increased water solubility up to 33%. The water absorption increased from 5 to 19 Pa·s and the paste viscosity from 5 to 339 Pa·s by extrusion processing. Analyses of dietary fiber contents and fiber polysaccharide structures revealed that thermo-mechanical stress (n = 700 min−1, mH2O = 22%) increased the content of soluble dietary fiber from 12.5 to 16.7 g/100 g dry matter, and that the harshest conditions even enabled the formation of low-molecular-weight dietary fiber. Arabinans (as neutral rhamnogalacturonan I side chains) appeared to be most sensitive to thermo-mechanical stress, whereas xylans (i.e., a group of minor polysaccharides) were an example of a more stable fiber polysaccharide. Also, the degree of methylation of the pectic polysaccharides was strongly reduced from 50% to 15% when thermo-mechanical stress was applied. Imaging and pore size analysis showed that extrusion processing could disrupt the rigid cell wall macromolecular structure.

scholarly journals Defined shear and heat treatment of apple pomace: impact on dietary fiber structures and functional properties

2021 ◽  
Author(s):  
Vera Schmid ◽  
Antje Trabert ◽  
Judith Keller ◽  
Mirko Bunzel ◽  
Heike P. Karbstein ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Dietary Fiber ◽  
High Temperatures ◽  
Functional Properties ◽  
Water Solubility ◽  
Apple Pomace ◽  
Type I ◽  
Closed Cavity ◽  
The Impact ◽  
By Products

AbstractFood by-products can be modified by extrusion processing. However, the impact of thermal and mechanical stress, respectively, on the structure and thus functional properties of dietary fiber-rich food by-products is still unknown. In the extrusion process, thermal and mechanical stress are coupled, not constant, and difficult to measure or calculate. Thus, their influence on structural changes and functional properties cannot be evaluated separately. In this work, a specific shear cell, denoted by closed cavity rheometer, was used to treat apple pomace with defined thermal and/or mechanical stress. Dietary fiber composition and fiber polysaccharide structures appeared to be more susceptible to high temperatures than mechanical stress. With increasing temperature (and mechanical stress) soluble and low-molecular-weight soluble dietary fiber contents increased, whereas insoluble fiber contents decreased. Arabinans as rhamnogalacturonan type I polysaccharides and galacturonic acid containing pectic polysaccharides were identified as being most susceptible to degradation under these conditions. Furthermore, the defined treatment affected the functional properties. Although changes in the water solubility index (WSI) and/or the water absorption index (WAI) were not detected up to 90 °C, WSI and WAI decreased significantly at a treatment temperature of 120 °C. However, at very high temperatures (160 °C), WSI and WAI increased. The application of shear and longer treatment times resulted in higher WSI values and complex viscosities as compared to low shear stress. Graphic abstract

scholarly journals Functionalization of Enzymatically Treated Apple Pomace from Juice Production by Extrusion Processing

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 485
Author(s):  
Vera Schmid ◽  
Antje Trabert ◽  
Judith (Schäfer) Keller ◽  
Mirko Bunzel ◽  
Heike P. Karbstein ◽  
...  
Keyword(s):  
Water Absorption ◽  
Dietary Fiber ◽  
Water Solubility ◽  
Apple Pomace ◽  
Raw Material ◽  
Food Ingredients ◽  
Insoluble Dietary Fiber ◽  
Extrusion Processing ◽  
The Impact ◽  
Treated Apple

Food by-products can be used as natural and sustainable food ingredients. However, a modification is needed to improve the technofunctional properties according to the specific needs of designated applications. A lab-scale twin-screw extruder was used to process enzymatically treated apple pomace from commercial fruit juice production. To vary the range of the thermomechanical treatment, various screw speeds (200, 600, 1000 min−1), and screw configurations were applied to the raw material. Detailed chemical and functional analyses were performed to develop a comprehensive understanding of the impact of the extrusion processing on apple pomace composition and technofunctional properties as well as structures of individual polymers. Extrusion at moderate thermomechanical conditions increased the water absorption, swelling, and viscosity of the material. An increase in thermomechanical stress resulted in a higher water solubility index, but negatively affected the water absorption index, viscosity, and swelling. Scanning electron microscopy showed an extrusion-processing-related disruption of the cell wall. Dietary fiber analysis revealed an increase of soluble dietary fiber from 12.6 to 17.2 g/100 g dry matter at maximum thermo-mechanical treatment. Dietary fiber polysaccharide analysis demonstrated compositional changes, mainly in the insoluble dietary fiber fraction. In short, pectin polysaccharides seem to be susceptible to thermo-mechanical stress, especially arabinans as neutral side chains of rhamnogalacturonan I.

scholarly journals Utilization of Food Processing By-products in Extrusion Processing: A Review

2021 ◽  
Vol 4 ◽  
Author(s):  
Debomitra Dey ◽  
Jana K. Richter ◽  
Pichmony Ek ◽  
Bon-Jae Gu ◽  
Girish M. Ganjyal
Keyword(s):  
Functional Properties ◽  
Low Cost ◽  
Value Added ◽  
Raw Material ◽  
Practical Applications ◽  
Extrusion Processing ◽  
High Production Rate ◽  
Wide Range ◽  
Extruded Products ◽  
By Products

The processing of agricultural products into value-added food products yields numerous by-products or waste streams such as pomace (fruit and vegetable processing), hull/bran (grain milling), meal/cake (oil extraction), bagasse (sugar processing), brewer's spent grain (brewing), cottonseed meal (cotton processing), among others. In the past, significant work in exploring the possibility of the utilization of these by-products has been performed. Most by-products are highly nutritious and can be excellent low-cost sources of dietary fiber, proteins, and bioactive compounds such as polyphenols, antioxidants, and vitamins. The amount of energy utilized for the disposal of these materials is far less than the energy required for the purification of these materials for valorization. Thus, in many cases, these materials go to waste or landfill. Studies have been conducted to incorporate the by-products into different foods in order to promote their utilization and tackle their environmental impacts. Extrusion processing can be an excellent avenue for the utilization of these by-products in foods. Extrusion is a widely used thermo-mechanical process due to its versatility, flexibility, high production rate, low cost, and energy efficiency. Extruded products such as direct-expanded products, breakfast cereals, and pasta have been developed by researchers using agricultural by-products. The different by-products have a wide range of characteristics in terms of chemical composition and functional properties, affecting the final products in extrusion processing. For the practical applications of these by-products in extrusion, it is crucial to understand their impacts on the qualities of raw material blends and extruded products. This review summarizes the general differences in the properties of food by-products from different sources (proximate compositions, physicochemical properties, and functional properties) and how these properties and the extrusion processing conditions influence the product characteristics. The discussion of the by-product properties and their impacts on the extrudates and their nutritional profile can be useful for food manufacturers and researchers to expand their applications. The gaps in the literature have been highlighted for further research and better utilization of by-products with extrusion processing.

Functional Properties and Dietary Fiber Characterization of Mango Processing By-products (Mangifera indica L., cv Ataulfo and Tommy Atkins)

2013 ◽  
Vol 68 (3) ◽  
pp. 254-258 ◽  
Author(s):  
María de Lourdes García-Magaña ◽  
Hugo S. García ◽  
Luis A. Bello-Pérez ◽  
Sonia G. Sáyago-Ayerdi ◽  
Miguel Mata-Montes de Oca
Keyword(s):  
Dietary Fiber ◽  
Functional Properties ◽  
Mangifera Indica ◽  
Fiber Characterization ◽  
By Products

scholarly journals Extraction of pectin from apple pomace

2005 ◽  
Vol 48 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Maria Helene Canteri-Schemin ◽  
Heloísa Cristina Ramos Fertonani ◽  
Nina Waszczynskyj ◽  
Gilvan Wosiacki
Keyword(s):  
Apple Pomace ◽  
Raw Material ◽  
Small Scale ◽  
Acid Extraction ◽  
Optimum Conditions ◽  
Citric Acid Concentration ◽  
Apple Variety ◽  
By Products ◽  
Time Of Reaction

As apple-processing units are now in expansion in Brazil, industrial by-products like pomace play an important role in pectin manufacture. The objective of this article was to determine a pratical follow-up to the extraction of pectin from apple pomace and to characterize it in a laboratory, on a small scale, aiming at establishing the optimum conditions for acid extraction. The highest yields were obtained when [1]apple pomace was dried and ground to obtain an apple flour to be used as raw material, [2] citric or nitric acids were used and [3] when the citric acid concentration was 6.2 g/100 ml and the time of reaction was 153 minutes. The apple variety in itself was not significant in pectin yield. The degree of esterification (DE = 68.84 %) of the product obtained, as well as its physical looks, show the success of pectin extraction.

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