Acidic pulping extractives

Fig. 2.56. HPLC chromatogram of (a) Golden peel and (b) Golden pulp extracts at 280 nm. Peaks 1 = procyanidin B3 2 = procyanidin Bl 3 = ( + )-catechin 4 = procyanin B2 5 = chlorogenic acid 6 = ( — )-epicatechin 7 = caffeic acid 8 = phloretin derivative 9 = phloridzin 10 = rutin 11, 12 and 13 = flavonol glucosides. Reprinted with permission from A. Escarpa et al. [160].

In a recent paper, 17 amino acids commonly present in Sauvignon wine from the Coastal region of Croatia were determined by complete assignment of their resonances by the use of aH and 13C NMR spectroscopy (Kosir and Kidric, 2001). In 2003, the metabolite content of the skin and pulp of mature berry extracts for four wines from the Bordeaux area were analyzed (Pereira et ah, 2005). Differences readily observed were due to an absence of polyphenol content in pulp extracts (Fig. 4.20). PCA highlighted that sugars were mainly responsible for cluster separation among samples in both types of extracts. 

The protein in citrus is generally associated with the solid portions of the fruit, i.e., the seeds, flavedo, albedo, chroma-tophores, and pulp. Some of these components find their way into the juice along with the available free amino acids during extraction and processing and storage. Studies conducted in our laboratories (42,43,44) and by others (45) have shown that reductions in the pulp content of juice slow the rate of browning. 

The pulp samples before and after the fungal degradation were air-dried and milled with Wiley Mill to flour (30 mesh). Lignin in pulp was isolated with the acidic dioxane extraction method described previously. Lignin extracted from die milled pulp before fungal degradation was used as a control. 

Polymers. Hydrocarbons from petroleum and natural gas serve as the raw material for virtually all polymeric materials commonly found in commerce, with the notable exception of rayon which is derived from cellulose extracted from wood pulp. Even with rayon, however, the cellulose is treated with acetic acid (qv), much of which is manufactured from ethylene (see Fibers, regenerated cellulosics). 

A pilot plant ia India has been estabUshed to extract fiber, pulp, and juice from the leaves of sisal plants. The fiber is sold direcdy or used to manufacture rope, the cmshed pulp is used ia paper processiag, and the juice is an excellent source of hecogenin. During a three- to five-day fermentation of the juice, partial enzymatic hydrolysis causes hecogenin to precipitate as the hemisaponin ia the form of a fine sludge. This sediment is hydrolyzed with aqueous hydrochloric acid, neutralized, and filtered. This filter cake is washed with water and extracted with alcohol. The yield of hecogenin varies between 0.05 and 0.1% by the weight of the leaf (126). 

Further Preparative Reactions. When pulps are to be used in the production of materials that do not retain the original fiber stmcture, such as rayon or ceUulose acetate film, the lignin, hemiceUulose, and other components must be reduced to the lowest possible concentrations. A surfactant (ionic or nonionic) is often added during a hot, weakly alkaline extraction step after chlorination. Another approach, sometimes used in addition to the surfactant step, is to treat the pulp with 6—10% NaOH after most of the oxidative bleaching is finished. This treatment removes most of the hemiceUulose. In most purification plants the final stage includes use of sulfuric acid chelators are optional. 

The manuf of NC is similar in that it involves the same nitrating acids as used for TNT, but used to treat cotton linters or wood pulp (raw cellulose) in a series of vats and reactors similar to the ones used for TNT. The crude NC is similarly subjected to a series of w and aq soln washes until it is finally delivered as a purified, fibrous mat — ordinarily wet with w or ale for safety. Again, there are major wastewater streams laden with spent reagents and extracted impurities... 

Marsh grapefhiit (MGF) pulp was homogenized in 5 volumes of extraction buffer at 4 C and maintained at pH 8.0 (28). The homogenate was stirred for one hour, centrifuged and the supernatant used as the PE extract. Activity was measured by titration with a Brinkman (Westbury, NY) pH stat titrator at pH 7.5 and 30°C in 25 mL of 1 % high methoxyl pectin (Citrus Colloids Limited, Hereford, UK) with O.IM NaCl. PE units are expressed as the microequivalents of ester hydrolysed per minute. Uronic acid analyses were conducted based on the m-phenyl phenol (4) as modified for microplate reading (30). 

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