Potato Juice Extraction

The goal of this step is to separate fiber from the starch-fiber cake with an acceptable starch loss. Some small fiber particles may remain in the rough starch. For fiber removal, diluted cake from the potato juice extraction is sieved in so-called centrifugal sieves. This type of sieve consists of a conical rotating sieve with perforations of 125 pm (Figure 11.13). 

FIGURE 7.14 Solubility of protein preparations as a function of pH. (a) Turbidity (expressed as absorbancy) of solutions of a whey protein isolate, heated at 70°C for various times (indicated, minutes). (From results by S. Damodaran, see Bibliography), (b) Solubility (percentage of protein in supernatant after centrifuging) of various protein products sodium caseinate (C), peanut (P), and soya (S) proteins. (Approximate results after various sources.) (c) Solubility (as in b) of the protein in a potato juice extract (pH = 7.0, 7=0.2 molar) as a function of solvent volume (v, in ml). See text for lines 1 and 2. (After results by G. A. van Koningsveld. Ph.D. thesis, Wageningen University, 2001.)... 

Lemon juice, instant mashed potatoes, beer Extraction with Polytron for 1 min, pH 2.0 for free and pH 8.9 for total sulfite Anion exclusion 6 mM H2S04... 

P-Enzyme was isolated from potato juice by Hanes in 1940 since then, preparations of various degrees of purity have been obtained from many higher plants. Potato P-enzyme has been intensively studied, and prepared in crystalline form. Extracts of the flagellate Polytomella coeca, which synthesizes a two-component starch, also contain P-enzyme. ... 

A variety of other SCF extraction processes have been explored fGupta and Johnston. 2008 Hover. 1985 McHugh and Krukonis. 1994 Paulaitis etal.. 19831. These include extraction of oils from seeds such as soybeans, removal of excess oil from potato chips, fruit juice extraction, extraction of oxygenated organics such as ethanol from water, dry cleaning, removal of lignite from wood, desorption of solutes from activated carbon, and treatment of hazardous wastes. Not all of these applications were successful, and many that were technically successful are not economical. 

Foam fractionation is a relatively inexpensive technique for protein separation. Most studies in the literature are, however, experimental and very few report on industrial appUcations. Among other appUcations, foam liaclionation has been used to separate wheat flour proteins, ovalbumin, lysozyme, egg albumin, milk proteins (e.g., beta-casein, bovine lactoferrin, bovine serum albumin, alpha-lactalbumin, and beta-lactoglobulin) and potato protein from potato juice waste water after starch extraction (Weijenberg et al., 1978 Keller et al., 1997 Hossain and Fenton, 1998 Brown et al., 1999 Wang and Liu, 2(X)3 Wang etal., 2009). 

Uses Antifoam for sugar beet and potato processing, juice extraction/purificalion, external water circulation systems of sugar factories Properties Liq. dens. 0.93 l /dm vise. 70 mPa-s add no. 2 max. sapon. no. 90-110 flash pt.>180C Environmental Biodeg. 

One source of ethanol is sugar cane or the molasses remaining after the juice has been extracted. Other plants such as potatoes, corn and other... 

While potato tuber is an important source of starch, it also contains 30-35 g buffer-extractable protein per kg dry weight (Pots et al., 1999). Protein yield per hectare of potatoes has been estimated as 500-1000 kg. The aqueous solution remaining after industrial potato starch manufacture, i.e., the potato fruit juice, contains approximately 1.5% (w/v) of soluble protein, mainly... 

A method has been developed for the analysis of the fungicide TBZ in fruits, potatoes, and their processed products. Extraction was performed with a basic solution (ethanol with 2 M ammonium chloride, pH 9.5, with 14.5 M ammonium hydroxide) and methylene chloride. Tribendazole was partitioned into methylene chloride with a polytron. No further cleanup was needed. Total analysis time, including extraction, was 25 min per sample. Recoveries ranged from 77 to 135%. Detection limits were 1.0 ppb for juice, fruits, and potatoes and 2 ppb for bulk concentrates (12). 

Difco Agar Yeast Extract (Difco) Corn meal Agar (Difco) Potato Dextrose V-8 Juice Agar (Campbell) (Difco) ... 

Potato extract, orange juice and yeast extract all stimulate the fermentation of glucose and acid production by propionic acid bacteria (Tatum et al., 1936). Stimulation by potato extract is associated with some essential growth factors. If synthetic medium is supplemented with yeast extract, then the addition of individual vitamins (biotin, pantothenate, thiamine or /7-aminobenzoic acid) is unnecessary (El-Hagarawy, 1957). In connection with the ability of P. shermanii to synthesize vitamins Karlin (1966) suggested to include these bacteria into dairy products. For example, kefir enriched with P. shermanii contained increased amounts of vitamin Bi, B2, Bg, PP, Bi2, pantothenate, folic and folinic acid as compared with control samples. Especially high increases in the latter four vitamins were observed. 

A reduction of dehydroascorbic acid (DHA) by sulfhydryl compounds occurs in the absence of enzyme. Pfankuch (19) reported on the presence, in potato extracts, of a heat-labile component that catalyzed this reaction. Hopkins and his collaborators (20, 21, 22) studied an enzyme, present in various plant juices, which markedly accelerated the reaction between GSH and DHA. Mapson and Goddard (17) coupled the reaction with GSSG reductase. Thus a complete hydrogen-transfer system from the substrate to oxygen, catalyzed by enzymes that occur in some plants, can be written as follows ... 

TPN can be dephosphorylated to DPN by phosphatases present in crude yeast juice and potato extract. Recently the activity has been purified 450-fold from extracts of pig kidney cortex. The properties of the purified enzjune resemble those of alkaline phosphatase, and it splits other nucleotides than TPN. Also, highly purified preparations of alkaline phosphatase are very active in converting TPN to DPN. The question remains open as to whether or not a specific enzyme exists which catalyzes this reaction. 

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