Influence of pre-treatment on yield and quality of mandarin juices Levaj, Branka (Faculty of Food Technology and Biotechnology, Zagreb (Croatia)); Putnik, Predrag (Faculty of Food Technology and Biotechnology, Zagreb (Croatia)); Linardić, Ivana (Faculty of Food Technology and Biotechnology, Zagreb (Croatia)) ...
Proceedings of 6th Central European Congress on Food - CEFood Congress,
2012
Conference Proceeding
Croatia in the Neretva valley produces remarkable quantities of mandarins but, as always, one part of yield, according to fruit characteristics, are not suitable for consumption as fresh. At the same ...time those fruit are suitable for processing industry e.g. for juice production. In Croatia, mandarin juice is not industrially produced, and generally is rare on market. The current study is contribution to mandarin juice processing with the aim to investigate influence of different pre-treatment on yield, quality, biological and sensorial attributes of obtained juices. Mandarin from Neretva valley was used to produce cloudy juices on small scale equipment. Before pressing, fruits were peeled and treated (i) with maceration enzymes at various temperature and duration (EPT) (ii) by ultrasound (USPT) with different amplitude and duration. Control juices were produced without enzymes or USPT. In juices biologically active compounds (BAS) total carotenoids (TC), total phenolics (TP), and vitamin C were determined. All juices were sensory evaluated (SE) by quantitative descriptive method. The results were statistically analyzed. Considering the investigated parameters there are no remarkable differences among juices produced by enzyme treatments independent of enzyme concentration, temperature (20 or 50 oC) and duration of 30 or 60 min. regarding to BAS and SE. Also, different US treatment conditions did not show any remarkable influence on investigated parameters. But in comparison of these two types of treatment better yield and SE were obtained by US and higher content of TC was obtained by enzyme treatment. Treatment by US could be recommended to produce mandarin juice due to high yield and SE but also further investigations are needed to optimize US conditions due to better preservation of BAS.
Introduction:
Obesity and related metabolic disturbances are frequently related to modern lifestyle and are characterized by excessive fructose intake. Visceral adipose tissue (VAT) inflammation has ...a central role in the development of insulin resistance, type 2 diabetes (T2D), and metabolic syndrome. Since sex-related differences in susceptibility and progression of metabolic disorders are not yet fully understood, our aim was to examine inflammation and insulin signaling in VAT of fructose-fed female and male adult rats.
Methods:
We analyzed effects of 9-week 10% fructose-enriched diet on energy intake, VAT mass and histology, and systemic insulin sensitivity. VAT insulin signaling and markers of VAT inflammation, and antioxidative defense status were also evaluated.
Results:
The fructose diet had no effect on VAT mass and systemic insulin signaling in the female and male rats, while it raised plasma uric acid, increased PPARγ level in the VAT, and initiated the development of a distinctive population of small adipocytes in the females. Also, adipose tissue insulin resistance, evidenced by increased PTP1B and insulin receptor substrate 1 (IRS1) inhibitory phosphorylation and decreased Akt activity, was detected. In addition, fructose stimulated the nuclear accumulation of NFκB, increased expression of proinflammatory cytokines (IL-1β, IL-6, and TNFα), and protein level of macrophage marker F4/80, superoxide dismutase 1, and glutathione reductase. In contrast to the females, the fructose diet had no effect on plasma uric acid and VAT inflammation in the male rats, but less prominent alterations in VAT insulin signaling were observed.
Conclusion:
Even though dietary fructose did not elicit changes in energy intake and led to obesity in the females, it initiated the proliferation of small-sized adipocytes capable of storing fats further. In contrast to the males, this state of VAT was accompanied with enhanced inflammation, which most likely contributed to the development of insulin resistance. The observed distinction could possibly originate from sex-related differences in uric acid metabolism. Our results suggest that VAT inflammation could precede obesity and start even before the measurable increase in VAT mass, making it a silent risk factor for the development of T2D. Our results emphasize that adipose tissue dysfunction, rather than its simple enlargement, could significantly contribute to the onset and development of obesity and related metabolic disorders.
Scope
Intake of fructose‐sweetened beverages and chronic stress (CS) both increase risk of cardiometabolic diseases. The aim is to investigate whether these factors synergistically perturb lipid ...metabolism in rat liver and kidney.
Methods and results
Fractional de novo lipogenesis (fDNL), intrahepatic‐ and intrarenal‐triglycerides (IHTG and IRTG), de novo palmitate (DNPalm) content, FA composition, VLDL‐TGs kinetics, and key metabolic gene expression at the end of the feeding and non‐feeding phases in rats exposed to standard chow diet, chow diet + CS, 20% liquid high‐fructose supplementation (HFr), or HFr+CS are measured. HFr induces hypertriglyceridemia, up‐regulates fructose‐metabolism and gluconeogenic enzymes, increases IHTG and DNPalm content in IHTG and IRTG, and augments fDNL at the end of the feeding phase. These changes are diminished after the non‐feeding phase. CS does not exert such effects, but when combined with HFr, it reduces IHTG and visceral adiposity, enhances lipogenic gene expression and fDNL, and increases VLDL‐DNPalm secretion.
Conclusion
Liquid high‐fructose supplementation increases IHTG and VLDL‐TG secretion after the feeding phase, the latter being the result of stimulated hepatic and renal DNL. Chronic stress potentiates the effects of high fructose on fDNL and export of newly synthesized VLDL‐TGs, and decreases fructose‐induced intrahepatic TG accumulation after the feeding phase.
High‐fructose supplementation increases plasma triglycerides (TGs) and decreases VLDL clearance, stimulates fractional de novo lipogenesis (fDNL) and increases de novo palmitate content, and stimulates both storage of TGs in the liver (IHTG) and VLDL‐TG secretion after the feeding phase. Stress potentiates the effects of fructose on fDNL, increases expression of lipogenic genes, and redirects the export of newly synthesized palmitate as VLDL‐TG.
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