John J. Powers

Effect of acidification of canned tomatoes on quality and shelf life

The review included a discussion of the reasons why acidification of canned tomatoes is sometimes desirable from a microbiological point of view, the possible Changes in the pH of tomatoes as a result of the breeding of new varieties, and the methods and suitable acids for acidification. Acidification does cause some minor differences in the chemical components of the canned product, but the differences appear to be inconsequential. Although can corrosion may be accelerated slightly, this again does not seem to be of practical importance. The can manufacturers recommend the same type of can whether or not tomatoes are acidified. Flavor studies almost invariably have indicated that tomatoes are as acceptable as nonacidified tomatoes at least down to pH 4.1 to 4.0. In fact, most studies show that acidified tomatoes are somewhat more acceptable. Reasons are suggested as to why outbreaks of botulism have occurred from home‐canned tomatoes, although the pH appears to have been below 4.5, and as to why outbreak...

Gas chromatography of methyl derivatives of naturally occurring capsaicinoids

Abstract A gas chromatographic method for the determination of the major naturally occurring capsaicinoids as O-methyl derivatives by on column derivatization with trimethylanilinium hydroxide was developed. Pure standards for quantitative gas chromatography were obtained from natural capsaicin by a combination of low pressure and semi-preparative high-performance liquid chromatography. Gas chromatographic on column methylation products were identified and conditions for maximum methylation were determined. The method was successfully applied to a wide variety of Capsicum products. Recoveries in the range of 99.1 to 102.4%, coefficients of variation in the range of 0.8 to 2.0% and ease of methylation make this method very suitable for capsaicinoid determination.

Some Biochemical and Physical Changes Occurring in Experimentally-Inflicted Poultry Bruises.

Summary Proteolytic activities, detected in experimentally-inflicted poultry bruises, were found to be influenced by many factors such as previous bruising, severity, and age of the bruise. Bruised tissues accumulated extrastromal hemoglobin which was degraded primarily to biliverdin in bruises contused on birds kept at 30° C and to bilirubin in birds kept at 21° C or below.

Effect of moisture level on volatile carbonyls in cottonseed oil heated to 210C

Cottonseed oil containing 0, 2.5, 5 and 10% added moisture was heated to simulate food-frying conditions. The volatile carbonyls from the heated oil were crystallized as 2,4-dinitrophenylhydrazones and then regenerated for separation by gas-liquid chromatography. Nineteen peaks were observed for the dry oil; oil with added moisture had fewer peaks. Oil containing added moisture produced more total carbonyl by weight than did dry oil. Maximum production of carbonyls occurred in the oil with 2.5% added moisture.

Effect of Anthocyanin Pigments on Certain Enzymes.

Summary The activities of alpha glucan phosphorylase and glutamic acid decarboxyl-ase increased when increasing amounts of 4 anthocyanin compounds were added to the substrate. The activities of glycerol dehydro-genase, malate dehydrogenase and hexokinase decreased except at the lowest concentration, 0.01%. At this level, the tendency was to increase slightly the activity of the enzymes studied. Possible explanations for the effect of anthocyanin pigments on the enzyme systems studied are discussed.

Pentafluorobenzylation of capsaicinoids for gas chromatography with electron-capture detection

Abstract The alkylation of capsaicinoids with pentafluorobenzyl (PFB) bromide for gas chromatography with electron-capture detection was studied. The PFB derivatives were formed within 30 min at 60°C and did not show any signs of decomposition. The alkylated capsaicinoids had a hydrophobic character making them suitable for gas chromatography on a non-polar column. The electron-capture response for the PFB derivatives of capsaicinoids was very sensitive and amounts of capsaicin down to 10 pg were easily detected. The method was succesfully applied to measurement of capsaicinoids in Capsicum products using vanillylamide of octanoic acid as an internal standard.

Search for the Determiners of Food Quality Ratings — Description of Methodology with Application to Blueberries

The object of this study is to relate qualitative and quantitative ratings as expressed by judges and to relate sensory responses to physical measurements and gas chromatograms. Judges were asked to rate acceptability, flavor, and mouthfeel of blueberries on a five-point scale in a darkened room. With another specimen, they were asked to judge appearance and color without, however, tasting these berries. The judges were also asked to complete a questionnaire describing, in qualitative terms, the characteristics of each specimen. Varieties were subjected to analysis by physical and chemical measurements, and gas chromatograms were prepared. Contingency analysis and analysis of variance were performed to relate qualitative and quantitative ratings. The relationship between physical measurements or chromatograms and ratings is displayed in tables of means; although these numbers can be expressed as single correlations, using a random model, a single measure based on just four products was deemed to be less informative than a tabulation of correspondence.

Inhibition of Enzymes by the Anthocyanin Malvidin-3-Monoglucoside.∗†

Summary The cytoplasmic, particulate, and cell wall fractions were isolated from disrupted bacterial cells and assayed for MADH, GDH, HX, and GLD enzymes in absence of pigment (control) and presence of various M-3-G concentrations. The magnitude of enzymatic inhibition due to increasing concentrations of M-3-G (1 to 4 μM) was not the same for each enzyme. Two μM of M-3-G inhibited glycerol dehydrogenase (35% of control) in particulate fraction, whereas, 76% inhibition was noted in cytoplasmic fraction with 4 μM of pigment. MADH was inhibited to the extent of 10 and 20% in particulate fraction with 2 and 4 μM of M-3-G respectively and 4% in cytoplasm with both pigment concentrations. For comparative purposes, the effect of M-3-G on the same enzymes obtained commercially from other sources revealed that GDH (Aerobacter aerogenes) was inhibited 85% with 4 μM pigment. Inhibition (87%) of MADH (pig heart) and (17%) GLD (Escherichia coli) was noted with 2 μM M-3-G. Stimulation of HX (yeast) (21% over control) was observed with 1 μM M-3-G; 2 μM had no effect, whereas 4 μM caused 6% inhibition. Competitive and non-competitive inhibition of GLD by M-3-G, depending on how substrate, inhibitor and enzyme were mixed, followed Michaelis-Menton kinetics as indicated by the linear relationship in the Lineweaver-Burk plot with Km = 2.3 × 10-5 M for enzyme and inhibitor equilibrated together and substrate added at zero time.

Industrial Food Wastes as Substrates for the Growth of Algae

Interest in unicellular, photosynthetic organisms has intensified in recent years. Particularly significant among these protista are the algae. The algal genus, Chlorella, has attracted the interest of scientists for its possible use äs a food source. The objectives of the study reported herein were (a) to learn whether industrial food wastes could serve äs suitable Substrates for the growth of algae, (b) to ascertain whether gibberellins added to such Substrates affected the rate of growth, yield, or composition of the algal cells, and (c) to determine whether the composition of the algal product was higher in protein than the Substrate upon which the cells were grown. Numerous scientists have studied or considered algae äs possible food sources (2, 14» 22). Several investigators have conducted feeding trials on chicks (3, 7) and rats (5, 6> 8, n), and the general tenor of such investigations is that algae are desirable and beneficial dietary constituents. Chlorella powder has been added to both Western and Japanese-style foods, giving them a favorable appearance and taste (17). Not only might algae be desirable for their food value per se, but the expansion of the food industry and many other industries has accentuated waste disposal problems (i, 23). The incorporation of wastes from processing plants into algal Substrates has been suggested (14) and the reclamation of nutrients from sewage and waste waters has been proposed (7). Chlorella and Eugkna have been grown on sewage in vi t ro (18) and a yeast-waste medium produced better yields than a modified Knops medium or a modified Knops-sucrose medium (21). The effects of gibberellins on algae have not been unequivocally established; however, there are several reports of increases in size and in air-dried weight of algae (4, 9, 12) with their use. The formation of cysts (9) and of increased number of zoospores (4) has also been observed. On the other hand, Kuo and Chang (13) found gibberellic acid had almost no effect on cell division and Gr i f f t n (9) even determined that 1000 ppm of gibberellic acid caused delayed reproduction and chlorosynthesis.

Effect of ascorbate on healing of poultry bruises.

Summary The level of ascorbate in the blood of normal birds was higher in birds kept at 7.2 and 21°C than in those raised at 30°C. Bruising resulted in a depletion of ascorbate in the blood probably due to utilization by the damaged tissues. Bruises injected daily with 2.0 mg Na-ascorbate healed at a much faster rate than bruises of non-treated birds. This treatment resulted in fast degradation of the hemoglobin present, mostly to bilirubin in birds kept at 30°C which normally accumulate biliverdin. Na-ascorbate reduced the size of the bruise and activated proteolytic enzyme in bruised tissue.