No abstract

Hand peeling of kiwi fruit has some disadvantages such as difficulty during peeling, increase of loss in weight and nutritional value. Peeling of kiwi fruits with alkali (NaOH) was investigated. Some chemical (acidity, pectin, and chlorophyll) and physical properties (Hunter color value and weight loss) of the fruits were determined after selected alkali peeling methods were used. Peeling methods at 80, 90 or 100C temperatures; in 13, 18 or 23% of NaOH solutions and for 3, 4 or 5 min durations were tested and compared with hand peeling. Weight (fruit tissue) loss in hand peeling was higher than alkali peeling. Peeling with alkali was easier. Nutritional value (ascorbic acid content) of alkali peeled fruits was higher than hand peeled kiwi fruit. Because of less weight loss, better green color and high pectin content the method including 15% of NaOH solution at 95C for 4 min was selected as most advantageous peeling method.

In this study, phenolic compounds and antioxidant activities in citrus fruits and their peels were determined, and their stimulatory roles on some lactic acid bacteria were investigated. Phenolic compounds in citrus fruits such as mandarin, lemon, orange and grapefruit were determined either in the juices or in the peel extracts. Total phenolic content was determined in a spectrophotometer at 685 nm using the adapted Folin-Ciocalteu method. Total flavonoid content was measured using LC/MS (liquid chromatography-mass spectrometry). The effects of the fruit juices and peel extracts on the selected lactic acid bacteria (Lactobacillus delbrueckii NRRL B5448, Lb. casei NRRL B1922, Lb. acidophilus NRRL B4495) were investigated. The tested lactic acid bacteria were significantly affected by chlorogenic acid, hesperidin, naringin and caffeic acid compared to the control samples (P?0.05). Antioxidant properties of fruit samples were also measured using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The phenolics positively affected the metabolism of bacteria, with the stimulatory effects of the assayed samples being influenced by the phenolic profile.

No abstract

Effects of modified atmosphere packaging (MAP) and potassium sorbate (PS) on total viable count (TVC) and yeast and mould counts (YMC) in sliced bread during storage were investigated. Gas combinations of air (control), 100% N 2 (A), 70% N 2 :30% CO 2 (B), 50% N 2 :50% CO 2 (C), 30% N 2 :70% CO 2 (D) and 100% CO 2 (E) and PS concentrations of 0, 0.15 and 0.30% were tested during 21 days of storage at ambient conditions (20±2°C and 60±2% RH). At the end of 21 days in all samples both with and without PS, the lowest YMC were in E. In air packed control without PS and with 0.15% PS, mould developed after 14 days storage. In addition to this, none of samples in all MAP treatments presented signs of mold at the end of the storage period (21 days). Similarly, E was the most effective treatment for the inhibition of bacteria. Also, it is concluded that 100 CO 2 atmospheres in MAP treatments and 0.15% PS addition to bread dough were sufficient for YM growth inhibition in sliced bread, in terms of human health. However, TVC was under 3 log cfu/g in only sample packaged with E and containing 0.30% PS until day 14.

No abstract

Spirulina produced in Turkey has a high antioxidant capacity determined by the three common methods (ABTS, CUPRAC, and DPPH). The major phenolics found in Spirulina were acacetin (53.62%) and pinocembrin (41.28%). The bio-accessibility values of the phenolic compounds in Spirulina were approximately 60%. PUFA's are the significant antioxidant compounds to prevent lipid peroxidation. Spirulina has been found to reduce blood sugar and oxidative stress due probably to the high amount of ω-6 PUFA. By the treatment of Spirulina, the levels of antioxidant enzymes (GSH-Px and SOD) were increased 240 and 60% in the healthy rats, while 19 and 59% in the diabetics. In diabetic rats fed with Spirulina, glucose, triglyceride, total cholesterol levels in blood and malondialdehyde content in body tissues were decreased by 20, 31, 22 and up to 56%, respectively. In-vitro and in-vivo tests have shown that Spirulina has anti-hyperglycaemic, anti-hyperlipidaemia and antioxidative effects on diabetic rats.

Chitosan is a modified, natural biopolymer derived by deacetylation of chitin. Mycelial growth of Penicillium chrysogenum, Fusarium oxysporum, Aspergillus parasiticus, As. fumigatus and As. niger was determined by measuring colony diameters on Petri plates. The red grape and honey melon samples inoculated with F. oxysporum were immersed into chitosan solution, and then kept at 4C for 7 days. The fungal isolates were tested using with seven concentrations of chitosan (0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%). The effective concentrations that require reducing the radial growth of the fungus on the media were determined as 57.6, 62.5 and 73.1% for Pe. chrysogenum, F. oxysporum and As. parasiticus, respectively. The chitosan coatings caused to decrease F. oxysporum growth in table grapes and honey melons and delayed changes in their external color. Chitosan is suitable to use as an antifungal edible film in the food industry in the near future. PRACTICAL APPLICATIONSChitosan has inhibitory activity for the growth of Penicillium chrysogenum, Fusarium oxysporum and Aspergillus parasiticus in vitro. Chitosan coatings can be used as an edible film for table grapes and honey cut melons. Hunter color values are better than the control samples for chitosan-coated fruits. It might be said that 1.5% w/v chitosan concentration can show optimum edible coating application for grapes and melons.