Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5·10(3) to 0.7·10(8) spores/g dry orange peel, the bed ...

Diacetyl has been associated with the "buttermilk off-flavor" sometimes found in orange juice and in frozen concentrated orange juice. Bacteria of the Lactobacillus and Leuconostoc genera have been identified as causative agents of this type of spoilage (Hays, 1951; Hays and Riester, 1952; Murdock et al., 1952, 1953; and Hill et al., 1954). Growth rates of these spoilage organisms have been inv...

Food additives, such as antioxidants and preservatives, are added to increase the shelf life of food items. In this Application Note, we describe a method to quantify an antioxidant (vitamin C) and preservatives (citric acid, benzoic acid) in orange juice. The method was developed on an Agilent 1260 Infinity LC system using an Agilent Poroshell EC-C18 column. Partial method validation was perfo...

The aim of this study was to compare tooth surface pH after drinking orange juice or water in 39 patients with dental erosion and in 17 controls. The following investigations were carried out: measurement of pH values on selected tooth surfaces after ingestion of orange juice followed by ingestion of water (acid clearance), measurement of salivary flow rate and buffering capacity. Compared with...

fertilizer plant waste carbon slurry has been investigated after some processing as an adsorbent for the removal of dyes and phenols using columns. the results show that the carbonaceous adsorbent prepared from carbon slurry being porous and having appreciable surface area (380 m2/g) can remove dyes both cationic (meldola blue, methylene blue, chrysoidine g, crystal violet) as well as anionic (...

A fluorometric method for the determination of N-nitroso-N-methylurea (NMU) has been developed. It is based on the N-methylation reaction of nicotinamide with NMU and a subsequent condensation reaction with acetophenone, followed by an acid treatment to form a fluorescent 2,7-naphthyridine derivative. This method enabled the determination of NMU in the range 0.05 - 2 nmol/200 microl with a rela...