Effect of extrusion conditions on the expansion of extruded apple pomace – wheat semolina mixtures

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.

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Development of a bidimensional analysis approach for n–butanol and electricity production in apple pomace biorefineries in a Mexican context

Biomass Conversion and Biorefinery ◽

10.1007/s13399-021-01472-3 ◽

2021 ◽

Author(s):

Carlos Eduardo Molina–Guerrero ◽

Idania Valdez–Vazquez ◽

María J. Macías–Mora ◽

Kathia León–Pérez ◽

José de Jesus Ibarra–Sánchez ◽

...

Keyword(s):

Apple Pomace ◽

Electricity Production ◽

Analysis Approach

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Biotransformation of Polyphenols in Apple Pomace Fermented by β-Glucosidase-Producing Lactobacillus rhamnosus L08

Foods ◽

10.3390/foods10061343 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1343

Author(s):

Lihua Liu ◽

Chenyi Zhang ◽

Huimin Zhang ◽

Guoqiang Qu ◽

Chun Li ◽

...

Keyword(s):

Lactic Acid ◽

Food Industry ◽

Antioxidant Activities ◽

Lactobacillus Rhamnosus ◽

Economic Benefits ◽

Apple Pomace ◽

High Cell ◽

Bioactive Components ◽

Glucosidase Activity ◽

Phenolic Profiles

Apple pomace, the main by-product in apple processing, is a cheap source of bioactive compounds that could be used in the food industry. However, the value of this by-product is still far from being fully realized. In this study, 11 strains of Lactobacillus strains were assayed for β-glucosidase activity, and only Lactobacillus rhamnosus L08 (L. rhamnosus L08) showed high cell-membrane associated β-glucosidase activity. We then evaluated the effects of fermentation of apple pomace using the selected strain, focusing on the biotransformation of polyphenols and antioxidant capacity. We found that L. rhamnosus L08 fermentation significantly reduced the contents of quercitrin and phlorizin in apple pomace, while increasing the contents of quercetin and phloretin. The contents of gallic acid, epicatechin acid, caffeic acid, and ferulic acid were also increased in apple pomace after fermentation. In addition, the antioxidant activities of apple pomace were enhanced during fermentation, based on the bioconversion of phenolic profiles. Our results demonstrate that lactic acid bacteria fermentation is a promising approach to enhance the bioactivity of phenolic compounds in apple pomace. Moreover, this study demonstrates that, as a valuable processing by-product with bioactive components, apple pomace can be used in the food industry to provide economic benefits.

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Apple Pomace as a Source of Bioactive Polyphenol Compounds in Gluten-Free Breads

Antioxidants ◽

10.3390/antiox10050807 ◽

2021 ◽

Vol 10 (5) ◽

pp. 807

Author(s):

Dorota Gumul ◽

Rafał Ziobro ◽

Jarosław Korus ◽

Marek Kruczek

Keyword(s):

Raw Materials ◽

Apple Pomace ◽

Total Phenolic ◽

Gluten Free ◽

Bioactive Substances ◽

Free Products ◽

Total Polyphenol ◽

Polyphenol Compounds ◽

High Oxidative Stress ◽

Vegetables And Fruits

Gluten-free products based on starch and hydrocolloids are deficient in nutrients and do not contain pro-health substances. Therefore, they should be enriched in raw materials naturally rich in antioxidants, especially if they are intended for celiac patients, prone to high oxidative stress. Apart from the traditionally used pseudo-cereals, seeds, vegetables and fruits, innovative substrates such as the by-product (especially in Poland) dry apple pomace could be applied. The study material consisted of gluten-free bread enriched with apple pomace. The content of individual polyphenols, the content of total polyphenol and flavonoids, and also the antioxidant potential of the bread were determined by the UPLC-PDA-MS/MS methods. It was observed that apple pomace was a natural concentrate of bioactive substances from the group of polyphenols. In summary, gluten-free bread with 5% content of apple pomace showed the highest organoleptic scores and contained high levels of phenolic compounds. The values of total phenolic content, and the amounts of flavonoids, phenolic acids and phloridzin in this bread were 2.5, 8, 4 and 21 times higher in comparison to control.

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