Determination of Lycopene Concentration in Fresh Tomatoes by Spectrophotometry: A Collaborative Study

BACKGROUND

Lycopene has been the object of considerable research attention recently, and the effects of the intake of lycopene, or of tomato products, have been studied in various ways. In Japan, interest in the health-promoting function of food components has increased.

OBJECTIVE

Developing a method to determine lycopene contents in tomato that meets the Japanese Agricultural Standard (JAS).

METHOD

In the proposed JAS method, the test sample consists of fresh tomatoes; a hexane-acetone mixture is utilized as the extraction solvent. A collaborative study was conducted to evaluate the interlaboratory performance of the method.

RESULTS

Ten laboratories participated and analyzed six test materials characterized by a lycopene content between 39 and 170 mg/kg as blind duplicates. After removing statistical outliers, RSDr ranged from 1.2 to 3.0% and RSDR ranged from 2.4 to 4.2%. The HorRat values were calculated and found to be in the 0.26-0.49 range.

CONCLUSIONS

The method for determining the lycopene content in tomato was evaluated by means of a collaborative study, and the reproducibility of this method was found to be acceptable.

HIGHLIGHTS

Intended for standardization in Japan, a method to determine lycopene content in tomato has been developed and shown to have acceptable precision in a collaborative study.

Determination of the Acid Value of Instant Noodles: Interlaboratory Study

An interlaboratory study was performed to evaluate the method for determining the acid value of instant noodles, based on the Japanese Agricultural Standard (JAS), with extraction of lipid using petroleum ether at a volume of 100 mL to the test portion of 25 g. Thirteen laboratories participated and analyzed 5 test samples as blind duplicates. Statistical treatment revealed that the repeatability (RSDR) of acid value was <6.5%, and the reproducibility (RSDR) of acid value was <9.6%. The HorRat values (RSDR/predicted RSDR) were 1.21.8, where the RSDR and the predicted RSDR were obtained in terms of free fatty acids in the noodles per unit weight, using the equation [acid value = percent free fatty acids (as oleic) 1.99] and the extracted lipid contents. This method was shown to have acceptable precision by the present study.

Determination of the moisture content of instant noodles: interlaboratory study

Determination of the moisture content of instant noodles, currently under discussion by the Codex Alimentarius Commission (CAC) requires 2 methods: one for fried noodles and the other for nonfried noodles. The method to determine the moisture content of fried noodles by drying at 105 degrees C for 2 h used in the Japanese Agricultural Standard (JAS) system of Japan can be applied to this purpose. In the present study, the JAS method for fried noodles was modified to be suitable for nonfried noodles by extending the drying time to 4 h. An interlaboratory study was conducted to evaluate interlaboratory performance statistics for these 2 methods. Ten participating laboratories each analyzed 5 test materials of fried and nonfried noodles as blind duplicates. After removal of outliers statistically, the repeatability (RSDr) and the reproducibility (RSD(R)) of these methods were 1.6-2.6 and 3.9-4.8% for fried noodles, and 0.3-1.5 and 1.3-2.9% for nonfried noodles, respectively.

Determination of the acid value of instant noodles: interlaboratory study

An interlaboratory study was performed to evaluate the method for determining the acid value of instant noodles, based on the Japanese Agricultural Standard (JAS), with extraction of lipid using petroleum ether at a volume of 100 mL to the test portion of 25 g. Thirteen laboratories participated and analyzed 5 test samples as blind duplicates. Statistical treatment revealed that the repeatability (RSDr) of acid value was <6.5%, and the reproducibility (RSDR) of acid value was <9.6%. The HorRat values (RSDR/predicted RSDR) were 1.2-1.8, where the RSDR and the predicted RSDR were obtained in terms of free fatty acids in the noodles per unit weight, using the equation [acid value = percent free fatty acids (as oleic) x 1.99] and the extracted lipid contents. This method was shown to have acceptable precision by the present study.

Method Performance Study of the Determination of Total Nitrogen in Soy Sauce by the Kjeldahl Method

The objective of this collaborative study was to evaluate the proposed method for determining the total nitrogen in soy sauce by the Kjeldahl method submitted to the Codex Alimentarius Commission for endorsement in accordance with the protocol for the design, conduct, and interpretation of method-performance studies. The digestive conditions of the proposed method are the addition of 10 mL of H2SO4, 10 g (8 g by using a block digester) of K2SO4, and 1 mL of 20% CuSO4 x 5H2O and 80 min boiling period after the liquid is cleared by a heating device. Seventeen laboratories participated, analyzing five soy sauce samples as blind duplicates. Since the volume sampling method used in the JAS (Japanese Agricultural Standard) method showed lower accuracy of data because of the density of soy sauce, the method of sampling by weight was adopted as the proposed method. The total amount of outlier data was within acceptable limits for method-performance studies (< or = 22.2%). Lysine and ammonium sulfate recoveries for all laboratories were > or = 98% and > or = 99% respectively. The RSDr (repeatability relative standard deviation) values ranged from 0.4 to 1.3%, and the RSDR (reproducibility relative standard deviation) values were from 0.8 to 1.9%. HORRAT (RSDR/predicted RSDR) for the reproducibility showed 0.2 to 0.4, indicating acceptable precision of the method and excellent analytical performance.

Intracranial electroencephalographic changes in deep anesthesia

OBJECTIVE

It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia.

METHODS

We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia.

RESULTS

The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0-2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of 'revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial 'revival' wave was followed by high-voltage burst-waves. In another case, at 2.0-2.5% of isoflurane, the amplitude of the waves was greatest on the EVG.

CONCLUSION

There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

[Isoflurane anesthesia with combined use of low dose fentanyl for open heart surgery]

The hemodynamic and respiratory effects of high dose fentanyl anesthesia and those of isoflurane anesthesia with combined use of low dose fentanyl were compared in 40 patients undergoing open heart surgery. Twenty patients (Group Fen) were anesthetized with high dose fentanyl (about 100 micrograms.kg-1), other twenty patients (Group Iso) were anesthetized with isoflurane (inhalation of 1.0-2.0%) combined with low dose fentanyl (about 8 micrograms.kg-1). Between the two groups, there were no significant differences in HR, CI, SVI, MPAP, MRAP, PVRI, RVCWI, LVSWI, DO2I, SvO2, and P/F ratio. In group Iso, there were significant decreases in mean arterial pressure (MAP) and systemic vascular resistance index (SVRI) at the time of sternotomy and before the cardiopulmonary bypass. In group Fen, a significant increase in VO2I occurred at the time of sternotomy. In ICU, catecholamine concentrations were significantly lower, and the duration of its use was significantly shorter in group Iso. Group Iso required significantly less time to awakening and to extubating. Therefore, group Iso shortened the length of ICU stays. In conclusion, isoflurane with combined use of low dose fentanyl anesthesia is an acceptable method of anesthesia for open heart surgery.

Effects on liver and serum lipids of dietary supplements of methionine and excess lysine given to previously-starved rats

The addition of lysine hydrochloride (50 g/kg) to a diet supplemented with methionine (3 g/kg) had no effect on liver lipids when rats (Wistar and Sprague-Dawley) were fed ad lib. for 14 d. However, refeeding a diet supplemented with methionine and excess lysine hydrochloride to previously-starved rats (Wistar) for 6, 7 or 9 d, but not 3 or 4 d, resulted in liver lipid accumulation, mainly triglycerides, which was prevented by the addition of arginine, citrulline, ornithine, adenine, allopurinol or maize oil, but not by guanine, cytosine, thymine or uracil. The addition of lysine hydrochloride to a methionine-supplemented diet resulted in reduced serum triglyceride levels after refeeding for 3 or 4 d and reduced serum cholesterol levels after refeeding for 3, 4 or 6 d. Serum lipids were unaffected by refeeding the diets for 7 or 9 d. Since hepatic lipid accumulation was preceded by the decline in the level of serum triglycerides, one of the factors responsible for lipid accumulation in the liver might be reduced transport of triglycerides from the liver into the blood. When adenine and allopurinol were added to the diet supplemented with methionine and lysine hydrochloride refed for 4 d, there was an increase in serum triglycerides. However, when this diet was refed for 7 d, with the addition of arginine, citrulline, guanine, pyrimidine bases, allopurinol or maize oil, no effects on serum cholesterol and triglyceride levels were observed.