Pasteurization Modifies the Sensorial Attributes and Nutritional Profile of Orange Pulp By-Product.

After orange processing, different by-products are generated, i.e., peels, seeds and pulps. The pulp is highly perishable, being an unstable food matrix that needs a preservation process to be stored and used again in the food production chain. Pasteurization is the technique of choice before aseptically packaging and storing under refrigerated conditions. In this study, the effect of pasteurization has been evaluated on the chemical, functional and sensorial profiles. Ash content decreased (p < 0.05) after the thermal treatment. Indeed, magnesium, calcium and zinc diminished, although copper was found to be higher (p < 0.05) in the pasteurized product. Total dietary fiber decreased (p < 0.05), but soluble dietary fiber raised (p < 0.05) due to hydrolysis caused by pasteurization. SDF:IDF ratio, hydration properties, and fat binding capacity were improved. Total soluble phenolic compounds remained similar but FRAP and DPPH scavenging activity decreased (p < 0.05) in the pasteurized by-product. Regarding the sensorial profile, pasteurization produced darkening, appearance of a cooked smell and an increase in bitterness. Therefore, pasteurization deteriorates the sensorial profile being able to change the attributes of an added-pasteurized-pulp juice; however, it is a good choice to preserve the orange pulp by-product to formulate food products different from juices or other beverages.

High Hydrostatic Pressure Assisted by Celluclast® Releases Oligosaccharides from Apple By-Product.

A novel and green procedure consisting of high hydrostatic pressure (HHP) aided by a commercial cellulase (Celluclast®) has been applied to valorise the apple by-product, a valuable source of dietary fibre but mainly composed by insoluble fibre. Optimal conditions for solubilisation of dietary fibre were first determined at atmospheric pressure as 2% (w/v) of substrate concentration and 20 Endo-Glucanase Units of cellulase. Monitoring of polysaccharides and oligosaccharides released from apple by-product was carried out by means of a newly validated HPLC method with refractive index detector. A synergistic effect was observed when the combined HHP plus cellulase treatment was used. Thus, the application of 200 MPa at 50 °C for 15 min enabled a significant increase in the release of water-soluble polysaccharides (1.8-fold) and oligosaccharides (3.8-fold), as well as a considerable decrease in the time required (up to 120-fold), compared to control at 0.1 MPa. Therefore, this technology could be a promising alternative approach to transform an industrial by-product into a novel rich-in-oligosaccharide food ingredient and a step forward into shaping the world of prebiotics.

Potential fat-lowering and prebiotic effects of enzymatically treated okara in high-cholesterol-fed Wistar rats.

This study evaluates the effect of the lipid profile on serum, liver and faeces, and the potential prebiotic effect of diets supplemented with enzymatically treated okara (okara(ET)) in high-cholesterol fed Wistar rats. Triglyceride levels were significantly reduced in the serum (p < 0.01) and liver (p < 0.01) of okara(ET) treated rats. Total lipids, triglycerides and bile acids were significantly higher (p < 0.001) in the faeces of rats fed the okara(ET) diet. The pH of faecal contents from treated okara(ET) rats was lower (p < 0.001), probably due to the significantly higher (p < 0.001) production of short-chain fatty acids (SCFA). Okara(ET), therefore, reduced triglycerides in serum and liver, and increased the excretion of total lipids, triglycerides and bile acids, improving the lipid profile in rats fed with high-cholesterol diets. Okara(ET) fibre can improve intestinal transit by increasing faecal bulk. The decreased pH and increased SCFA production indicated that okara(ET) fibre fermentation occurred, suggesting a potential prebiotic effect.

Broad bean and pea by-products as sources of fibre-rich ingredients: potential antioxidant activity measured in vitro.

BACKGROUND: By-products generated during the processing of plant food can be considered a promising source of dietary fibre as a functional compound. The dietary fibre composition, soluble sugars and antioxidant activity of the extractable polyphenols of pea and broad bean by-products have been analysed in this study. RESULTS: Total dietary fibre using AOAC methods plus hydrolysis (broad bean pod: 337.3 g kg⁻¹; pea pod: 472.6 g kg⁻¹) is higher (P < 0.05) in both by-products than with the Englyst method (broad bean pod: 309.7 g kg⁻¹; pea pod: 434.6 g kg⁻¹). The main monomers are uronic acids, glucose, arabinose and galactose in broad bean pods. However, pea pods are very rich in glucose and xylose. The soluble sugars analysed by high-performance liquid chromatography in both by-products have glucose as the most important component, followed by sucrose and fructose. The ferric reducing antioxidant power (broad bean pod: 406.4 µmol Trolox equivalents g⁻¹; pea pod: 25.9 µmol Trolox equivalents g⁻¹) and scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radical (EC50 of broad bean pod: 0.4 mg mL⁻¹; EC50 of pea pod: 16.0 mg mL⁻¹) were also measured. CONCLUSIONS: Broad bean and pea by-products are very rich in dietary fibre, particularly insoluble dietary fibre and their extractable polyphenols demonstrate antioxidant activity. Therefore they might be regarded as functional ingredients.