INSECT FATS FOR COSMETICS 195 macadamia nut oil) and the fractionated BSF fractions (FFAs phospholipids cholesteryl esters triglycerides cholesterol diglycerides monoglycerides) are presented. Comparison of the insect fats, mink oil, vegetal oil, and macadamia nut oil with the fat fractions indicates that BSF and cricket fats contain a rather large proportion of FFAs. In locust fat, the number of FFAs is lower. In the oils that are typically used in cosmetics (Figure 1, Lanes 5 and 6), the fraction of FFAs is limited but these oils have been thoroughly refi ned. Phospholipids (a spot close to the bottom of the TLC plate) can also be seen in the BSF, cricket, and locust fats and is almost absent in the refi ned fats. Fractions that are abundantly present in all oils are the triglycerides and the diglycerides. Cholesteryl esters and monoglycerides are hard to observe in the samples. Refi ning of the raw fats (starting with 50–150 g of fat) encompassed a total degumming, neutralization, bleaching, and deodorization procedure. Bleaching and deodorization had only slight effects, but the fats became less dark and the odor less pronounced (data not shown). The locust fat had a greenish color that was hypothesized to be due to the presence of chlorophyll as the locusts were fed grass. This was verifi ed spectrophotometrically as the UV–vis spectrum showed the typical absorption bands of chlorophyll (data not shown). To evaluate the refi ning process and to characterize the fats, the acid values, which are a measure of the FFA content, were determined. The acid values of the fats are shown in Table III. These values are high compared with the acid values of the thoroughly refi ned mink oil (0.48 mg/g fat according to the manufacturer’s specifi cations) and macadamia nut oil (0.13 mg/g fat according to the manufacturer’s specifi cations). This indicates a signifi cant presence of FFAs in the raw insect fat fraction. Although locusts still contain a considerable amount of about 20 mg of FFAs/g fat, this is far less than what is found in BSF and cricket fats. These values are corroborated by the Fourier-Transform Infrared Spectroscopy (FTIR) spectra (Figure 2), which show the presence of a signifi cant peak around 1,710 cm-1 in the case of the cricket fat and a far less intense peak in the case of locust fat. The peak around 1,710 cm-1 can be attributed to the presence of the C=O stretching of the carboxyl group of FFAs, whereas the absorption band at 1,743 cm-1 arises from the C=O stretching of the ester carbonyl group of the triglycerides (23). The FTIR data also illustrate the effect of refi nement on decreasing the amount of FFAs within the three insect fats. FATTY ACID PROFILE The fatty acid profi les of the three insect species were determined by GC–MS and are presented in Table IV. The table also includes typical average values for mink oil and macadamia nut oil (information provided by suppliers). There is a large difference in fatty acid composition between BSF and the two other species. BSF fat stands out with its high Table III Average Acid Value (mg FFA/g Fat) of Fats of three Insect Species Species Average acid value (Soxhlet) Average acid value (large extraction) BSF 91.6 (N = 2) 86.2 (N = 7) House cricket 74.4 (N = 2) 68.1 (N = 5) Locust 22.2 (N = 2) 20.7 (N = 3)

JOURNAL OF COSMETIC SCIENCE 196 Figure 2. FTIR spectra (1,60 0–1,800 cm-1) of BSF (A), cricket (B) and locust (C) fats raw fats solid line, refi ned fats dotted line).