Pineapple (Ananas comosus L.) By-Products Valorization: Novel Bio Ingredients for Functional Foods

Abstract

Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30-50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse and renewal flows in an integrated process to promote economic growth by reducing consumption of natural resources and diminishing food waste. In our study, pineapple shell (PS) and pineapple core (PC), vacuum-packed separately, were subjected to moderate hydrostatic pressure (225 MPa, 8.5 min) (MHP) as abiotic stress to increase bromelain activity and antioxidant capacity. Pressurized and raw PBP were lyophilized to produce a stable powder. The dehydrated samples were characterized by the following methodologies: chemical and physical characterization, total phenolic compounds (TPC), antioxidant capacity, bromelain activity, microbiology, and mycotoxins. Results demonstrated that PBP are naturally rich in carbohydrates (66-88%), insoluble (16-28%) and soluble (2-4%) fiber, and minerals (4-5%). MHP was demonstrated to be beneficial in improving TPC (2-4%), antioxidant activity (2-6%), and bromelain activity (6-32%) without affecting the nutritional value. Furthermore, microbial and mycotoxical analysis demonstrated that powdered PC is a safe by-product. PS application is possible but requires previous decontamination to reduce the microbiological load.

Keywords: bioactive compounds; novel food ingredient; pineapple by-products; sustainability.

Figure 1

Total phenolic content in pineapple shell (PS) and pineapple core (PC) samples before and after pressurization (shell, PPS; core, PPC). Error bars represent ± standard deviation (n = 9). Different letters express significant differences between pineapple shell (lowercase letters) and pineapple core samples (capital letters).

Figure 2

Antioxidant activity in pineapple shell (PS) and pineapple core (PC) samples, before and after pressurization (shell: PPS; core: PPC), by methods: (a) DPPH (2,2-diphenyl-1-picrylhydrazyl), (b) FRAP (Ferric Reducing Antioxidant Power), and (c) ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)). The results were expressed by Trolox Equivalent Antioxidant Capacity (TEAC). Error bars represent ± standard deviation (n = 9). Statistical analysis express significant differences between pineapple shell and pressurized pineapple shell for DPPH (lowercase letters), FRAP (lowercase roman numeral) and ABTS (white ordinal number), and between pineapple core and pressurized pineapple core for DPPH (capital letters), FRAP (capital roman numeral), and ABTS (black ordinal number).

Figure 3

Bromelain activity in pineapple shell (PS) and pineapple core (PC) samples before and after pressurization (shell: PPS; core: PPC). Error bars represent ± standard deviation (n = 9). Different letters express significant differences between pineapple shell (lowercase letters) and pineapple core samples (capital letters).