Utilization and evaluation of Citrus natsudaidai peel waste as a source of natural food additives.

This study aims to obtain beneficial ingredients from Citrus natsudaidai (CN) peel waste. The yields of ingredients were 26.2-31.6 mg/g dried material (DM) in pectin, 466-581 mg/g DM in insoluble dietary fiber, 5.56-7.15 g/kg fresh material (FM) in the hexane extracts obtained from CN peels, 23.8-27.0 mg/g DM in naringin, and 8.30-10.2 mg/g DM in neohesperidin. A sensory evaluation and instrumental assays using an Electronic nose and Electronic tongue were performed to evaluate aqueous solutions flavored with 0.02% hexane extracts obtained from CN peels. CN-flavored solutions had a preferred smell over commercial citrus-flavored drinks and were classified into the same group as commercial citrus juices in the Electronic nose assay. In addition, CN-flavored solutions showed sourness, bitterness, and orange-like taste, and the overall acceptance of CN-flavored solutions did not significantly differ from commercial citrus-flavored drinks. CN peel waste can be industrially utilized as a source of natural food additives.

Proximate composition and profiles of free amino acids, fatty acids, minerals and aroma compounds in Citrus natsudaidai peel.

Bulky hard peel of Citrus natsudaidai is discarded and not utilized enough in Japan. In this study, the nutritional composition and volatile components of three cultivars of C. natsudaidai peel were determined. Considering the proximate composition and minerals, C. natsudaidai peels showed good carbohydrate and potassium content. The peel color varied probably due to the difference of cultivars. C. natsudaidai peels were extracted and analyzed for free amino acids and for fatty acids and volatile compounds. The amount of free amino acids in the extracts was not enough to affect the taste of extracts. The proportion of individual fatty acid was not comparable to other plant oils, however, typical aroma compounds with citrusy smell were identified. C. natsudaidai extracts could contribute for the utilization as flavoring additives without affecting taste.

Functional properties, lipoxygenase activity, and health aspects of Lupinus albus protein isolates.

To utilize lupin seeds for food and pharmaceutical applications, lupin seeds were pretreated to remove oil using hexane or carbon dioxide. Two types of lupin protein isolate were prepared. Both types of protein isolate showed good foaming activity, comparable to egg white. Protein isolate extracted under acid conditions showed higher foaming activity than protein isolate extracted at neutral pH. The lipoxygenase activity was much reduced in both of the protein isolates. The protein isolate extracted at neutral pH showed a stronger angiotensin converting enzyme inhibition than the protein isolate extracted under acidic pH. In contrast, the protein isolate extracted under acid conditions had a greater sodium cholate binding capacity, comparable to that of cholestyramine. Lupin samples showed less DPPH radical scavenging activity than deoiled soybean. The deoiling method did not affect the functional properties, lipoxygenase activity, angiotensin converting enzyme inhibition, sodium cholate binding, and radical scavenging activity.